WorldWideScience

Sample records for natural spontaneously fissile

  1. 49 CFR 173.420 - Uranium hexafluoride (fissile, fissile excepted and non-fissile).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Uranium hexafluoride (fissile, fissile excepted....420 Uranium hexafluoride (fissile, fissile excepted and non-fissile). (a) In addition to any other... non-fissile uranium hexafluoride must be offered for transportation as follows: (1) Before...

  2. The nature of spontaneous cavernosal activity.

    Science.gov (United States)

    Colakoglu, Z; Kutluay, E; Ertekin, C

    1999-03-01

    To determine the characteristics of spontaneous cavernosal activity (SCA) and to relate this to previous descriptions of spontaneous potentials from the cavernosum (single potential analysis of cavernosal activity, SPACE). The SCA was recorded in 31 normal men with no sexual problems; various manipulations were applied using concentric-needle (CN), bipolar needle (BN) and surface electrodes. The electrical activity was compared with the observed slow retractile movements of the flaccid penis and with other assessments of electrical activity from skin. SCA appeared synchronously from both sides of the cavernosal bodies in all normal subjects when detected by CN electrodes. The synchronous recordings both by CN and BN electrodes, or both by CN and surface electrodes registered similar oscillatory potentials. Slow retractile movements of the penis occurred synchronously with these potentials in all subjects and both were absent during erection. SCA is apparently related to biomechanical slow movement artefacts of the flaccid penis: it may be a consequence of the summed contractions of smooth muscle groups in the cavernosum. Observing the small retractile slow movements of the flaccid penis and recording the SCA may be a useful indirect method to characterize cavernosal neural innervation and smooth muscle activity.

  3. The nature of spontaneous sleep across adulthood.

    Science.gov (United States)

    Campbell, Scott S; Murphy, Patricia J

    2007-03-01

    The decline in sleep quality that often accompanies aging is thought to be the consequence of alterations in both circadian and homeostatic processes widely assumed to be responsible for sleep/wake regulation. A number of experimental approaches have been used to examine various aspects of age-related sleep changes, but none has examined spontaneous sleep across the entire 24-h day. Using the 'disentrainment' protocol, we studied such sleep in young, middle-aged and older adults. All subjects exhibited polyphasic sleep patterns, characterized by relatively short intervals of both sleep and waking. Whereas, the average duration of major nighttime sleep was significantly shorter in middle-aged and older subjects than in young adults, daytime napping was essentially unaffected by age. Comparisons of sleep and circadian variables between age groups suggest differential effects on sleep of the two regulatory processes, with changes in homeostatic drive preceding those of the circadian component. These findings add to a surprisingly scant literature on the longitudinal decline in sleep quality associated with aging.

  4. Spontaneous natural optical activity in disordered media

    CERN Document Server

    Pinheiro, F A; Papasimakis, N; Zheludev, N I

    2016-01-01

    We demonstrate natural optical activity in disordered ensembles of non-chiral plasmonic resonators. We show that the statistical distributions of rotatory power and spatial dichroism are strongly dependent on the scattering mean free path in diffusive random media. This result is explained in terms of the intrinsic geometric chirality of disordered media, as they lack mirror symmetry. We argue that chirality and natural optical activity of disordered systems can be quantified by the standard deviation of both rotatory power and spatial dichroism. Our results are based on microscopic electromagnetic wave transport theory coupled to vectorial Green's matrix method for pointlike scatterers, and are independently confirmed by full-wave simulations.

  5. Fissile mass estimation by pulsed neutron source interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Israelashvili, I., E-mail: israelashvili@gmail.com [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Dubi, C.; Ettedgui, H.; Ocherashvili, A. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Pedersen, B. [Nuclear Security Unit, Institute for Transuranium Elements, Joint Research Centre, Via E. Fermi, 2749, 21027 Ispra (Italy); Beck, A. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Roesgen, E.; Crochmore, J.M. [Nuclear Security Unit, Institute for Transuranium Elements, Joint Research Centre, Via E. Fermi, 2749, 21027 Ispra (Italy); Ridnik, T.; Yaar, I. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel)

    2015-06-11

    Passive methods for detecting correlated neutrons from spontaneous fissions (e.g. multiplicity and SVM) are widely used for fissile mass estimations. These methods can be used for fissile materials that emit a significant amount of fission neutrons (like plutonium). Active interrogation, in which fissions are induced in the tested material by an external continuous source or by a pulsed neutron source, has the potential advantages of fast measurement, alongside independence of the spontaneous fissions of the tested fissile material, thus enabling uranium measurement. Until recently, using the multiplicity method, for uranium mass estimation, was possible only for active interrogation made with continues neutron source. Pulsed active neutron interrogation measurements were analyzed with techniques, e.g. differential die away analysis (DDA), which ignore or implicitly include the multiplicity effect (self-induced fission chains). Recently, both, the multiplicity and the SVM techniques, were theoretically extended for analyzing active fissile mass measurements, made by a pulsed neutron source. In this study the SVM technique for pulsed neutron source is experimentally examined, for the first time. The measurements were conducted at the PUNITA facility of the Joint Research Centre in Ispra, Italy. First promising results, of mass estimation by the SVM technique using a pulsed neutron source, are presented.

  6. Spontaneous pion emission as a new natural radioactivity

    Science.gov (United States)

    Ion, D. B.; Ivascu, M.; Ion-Mihai, R.

    1986-10-01

    In this paper the pionic nuclear radioactivity or spontaneous poin emission by a nucleus from its ground state is investigated. The Qπ-values as well as the statistical factors are calculated using the experimental masses tabulated by Wapstra and Audi. Then it was shown that the pionic radioactivity of the nuclear ground state is energetically possible via three-body channels for all nuclides with Z > 80. This new type of natural radioactivity is statistically favored especially for Z = 92 - 106 for which F π/F SF = 40 - 200 [ MeV] 2. Experimental detection of the neutral pion and also some possible emission mechanisms are discussed.

  7. Spontaneous pion emission as a new natural radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Ion, D.B.; Ivascu, M.; Ion-Mihai, R.

    1986-10-15

    In this paper the pionic nuclear radioactivity or spontaneous pion emission by a nucleus from its ground state is investigated. The Q/sub ..pi../-values as well as the statistical factors are calculated using the experimental masses tabulated by Wapstra and Audi. Then it was shown that the pionic radioactivity of the nuclear ground state is energetically possible via three-body channels for all nuclides with Z>80. This new type of natural radioactivity is statistically favored especially for Z = 92-106 for which F/sub ..pi..//F/sub S//sub F/ = 40-200 (MeV)/sup 2/. Experimental detection of the neutral pion and also some possible emission mechanisms are discussed.

  8. Accelerating fissile fuel breeding in FBR with natural safety features%加速增产核燃料的天然安全“核热泉”快中子增殖堆

    Institute of Scientific and Technical Information of China (English)

    吕应中

    2012-01-01

    为保证21世纪中国经济的持续稳定地高速增长,必须充分发挥核能的巨大潜力,使之配合其他可再生能源同步增长,及早大规模替代煤炭等化石能源.由于目前国内大量兴建的核电站以压水堆为主,需要消费大量天然铀资源,倚靠廉价铀供应难于维持长期增长,必须依靠快中子增殖生产人造裂变燃料——钚,才能摆脱天然铀原料短缺的束缚.然而,传统的快中子增殖堆的核燃料增产速度较慢,难于配合中国核电的高速增长.本文介绍一种先进快中于增殖堆(AFBR)方案,其中利用在线连续换料的空心球形燃料元件,依靠载热剂的出人口之间的温度差实现满功率自然循环,可以成倍地提高燃料比功率与核燃料增殖速度.本快中子增殖堆改进了俄罗斯称为“天然安全”的BREST铅冷快堆设计方案,成为无须人为控制的“核热泉”,它能在不设置加压泵及高位铅池的情况下,自动按外部负荷需要供应必要的热量,完全依靠自然循环将全部裂变热能及停堆后堆芯余热散出,不至对环境产生放射性污染.%To guarantee the rapid growth of the Chinese economy in 21" century, nuclear energy should be fully exploited, together with other renewable energies to replace coal and other depletive fossil fuels. Unfortunately, the major Chinese nuclear power plants under construction are mostly PWRs that would consume a lot of natural uranium during their operations. The availability of cheap natural uranium could seriously constraint the Chinese nuclear power development, unless artificial fissile fuel-plutonium is supplied from fast breeder reactors. The fissile nuclei production rate in the traditional fast breeders, however, seems too slow to match the rapid growth of nuclear power. A concept of the advanced fast breeder (AFBR) is introduced, therefore, to greatly accelerating the fissile fuel breeding process. In said breeder, the spherical hollow

  9. Fissile solution dynamics: Student research

    Energy Technology Data Exchange (ETDEWEB)

    Hetrick, D.L.

    1994-09-01

    There are two research projects in criticality safety at the University of Arizona: one in dynamic simulation of hypothetical criticality accidents in fissile solutions, and one in criticality benchmarks using transport theory. We have used the data from nuclear excursions in KEWB, CRAC, and SILENE to help in building models for solution excursions. An equation of state for liquids containing gas bubbles has been developed and coupled to point-reactor dynamics in an attempt to predict fission rate, yield, pressure, and kinetic energy. It appears that radiolytic gas is unimportant until after the first peak, but that it does strongly affect the shape of the subsequent power decrease and also the dynamic pressure.

  10. Formation of oil-in-water emulsions from natural emulsifiers using spontaneous emulsification: sunflower phospholipids.

    Science.gov (United States)

    Komaiko, Jennifer; Sastrosubroto, Ashtri; McClements, David Julian

    2015-11-18

    This study examined the possibility of producing oil-in-water emulsions using a natural surfactant (sunflower phospholipids) and a low-energy method (spontaneous emulsification). Spontaneous emulsification was carried out by titrating an organic phase (oil and phospholipid) into an aqueous phase with continuous stirring. The influence of phospholipid composition, surfactant-to-oil ratio (SOR), initial phospholipids location, storage time, phospholipid type, and preparation method was tested. The initial droplet size depended on the nature of the phospholipid used, which was attributed to differences in phospholipid composition. Droplet size decreased with increasing SOR and was smallest when the phospholipid was fully dissolved in the organic phase rather than the aqueous phase. The droplets formed using spontaneous emulsification were relatively large (d > 10 μm), and so the emulsions were unstable to gravitational separation. At low SORs (0.1 and 0.5), emulsions produced with phospholipids had a smaller particle diameter than those produced with a synthetic surfactant (Tween 80), but at a higher SOR (1.0), this trend was reversed. High-energy methods (microfluidization and sonication) formed significantly smaller droplets (d < 10 μm) than spontaneous emulsification. The results from this study show that low-energy methods could be utilized with natural surfactants for applications for which fine droplets are not essential.

  11. Spontaneous reconnection at a separator current layer. II. Nature of the waves and flows

    CERN Document Server

    Stevenson, Julie E H

    2015-01-01

    Sudden destabilisations of the magnetic field, such as those caused by spontaneous reconnection, will produce waves and/or flows. Here, we investigate the nature of the plasma motions resulting from spontaneous reconnection at a 3D separator. In order to clearly see the perturbations generated by the reconnection, we start from a magnetohydrostatic equilibrium containing two oppositely-signed null points joined by a generic separator along which lies a twisted current layer. The nature of the magnetic reconnection initiated in this equilibrium as a result of an anomalous resistivity is discussed in detail in \\cite{Stevenson15_jgra}. The resulting sudden loss of force balance inevitably generates waves that propagate away from the diffusion region carrying the dissipated current. In their wake a twisting stagnation-flow, in planes perpendicular to the separator, feeds flux back into the original diffusion site (the separator) in order to try to regain equilibrium. This flow drives a phase of slow weak impulsiv...

  12. Extralobar pulmonary sequestration in neonates: The natural course and predictive factors associated with spontaneous regression

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Hee Mang; Jung, Ah Young; Cho, Young Ah; Yoon, Chong Hyun; Lee, Jin Seong [Asan Medical Center Children' s Hospital, University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Songpa-gu, Seoul (Korea, Republic of); Kim, Ellen Ai-Rhan [University of Ulsan College of Medicine, Division of Neonatology, Asan Medical Center Children' s Hospital, Seoul (Korea, Republic of); Chung, Sung-Hoon [Kyung Hee University School of Medicine, Department of Pediatrics, Seoul (Korea, Republic of); Kim, Seon-Ok [Asan Medical Center, Department of Clinical Epidemiology and Biostatistics, Seoul (Korea, Republic of)

    2017-06-15

    To describe the natural course of extralobar pulmonary sequestration (EPS) and identify factors associated with spontaneous regression of EPS. We retrospectively searched for patients diagnosed with EPS on initial contrast CT scan within 1 month after birth and had a follow-up CT scan without treatment. Spontaneous regression of EPS was assessed by percentage decrease in volume (PDV) and percentage decrease in sum of the diameter of systemic feeding arteries (PDD) by comparing initial and follow-up CT scans. Clinical and CT features were analysed to determine factors associated with PDV and PDD rates. Fifty-one neonates were included. The cumulative proportions of patients reaching PDV > 50 % and PDD > 50 % were 93.0 % and 73.3 % at 4 years, respectively. Tissue attenuation was significantly associated with PDV rate (B = -21.78, P <.001). The tissue attenuation (B = -22.62, P =.001) and diameter of the largest systemic feeding arteries (B = -48.31, P =.011) were significant factors associated with PDD rate. The volume and diameter of systemic feeding arteries of EPS spontaneously decreased within 4 years without treatment. EPSs showing a low tissue attenuation and small diameter of the largest systemic feeding arteries on initial contrast-enhanced CT scans were likely to regress spontaneously. (orig.)

  13. Technologies for Fissile Material Detection and Prevention of Fissile Material Introduction into International Shipping

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, J

    2003-07-01

    Prevention of the introduction of fissile materials into international shipping, and hence into a given country, is a complex problem. Some pieces of the solution to the puzzle are conceptually well defined, but lack definition of a technical pathway and/or operational implementation. Other elements are a little more fuzzy, and some elements are probably undefined at this point in time. This paper reviews the status of the more well-defined elements, and suggests needed additional measures to enhance the probability that fissile materials are not illicitly introduced into distant countries. International commerce proceeds through a number of steps from point of origin to final destination. Each step offers the possibility of a well-defined choke point to monitor and interdict the illicit shipment of fissile materials. However, because there are so many potential points and venues of entry into a large country such as the United States (e.g., air cargo, shipping containers, truck and rail transport, private vehicles, boats and planes, commercial passenger travel), it behooves the world to ensure that fissile material does not illicitly leave its point of origin.

  14. 49 CFR 173.477 - Approval of packagings containing greater than 0.1 kg of non-fissile or fissile-excepted uranium...

    Science.gov (United States)

    2010-10-01

    ... kg of non-fissile or fissile-excepted uranium hexafluoride. 173.477 Section 173.477 Transportation... non-fissile or fissile-excepted uranium hexafluoride. (a) Each offeror of a package containing more than 0.1 kg of uranium hexafluoride must maintain on file for at least one year after the...

  15. Nature of unusual spontaneous and field-induced phase transitions in multiferroics RMn 2O 5

    Science.gov (United States)

    Pyatakov, A. P.; Kadomtseva, A. M.; Vorob'ev, G. P.; Popov, Yu. F.; Krotov, S. S.; Zvezdin, A. K.; Lukina, M. M.

    2009-04-01

    Complex magnetic, magnetoelectric and magnetoelastic studies of spontaneous and field-induced phase transitions in TmMn 2O 5 were carried out. In the vicinity of spontaneous phase transition temperatures (35 and 25 K) the magnetoelectric and magnetoelastic dependences demonstrated the jumps of polarization and magnetostriction induced by the field ˜150 kOe. These anomalies can be attributed to the influence of magnetic field on the conditions of incommensurate-commensurate phase transition at 35 K and the reverse one at 25 K. In b-axis dependences the magnetic field-induced spin-reorientation phase transition was also observed below 20 K. Finally the magnetoelectric anomaly associated with metamagnetic transition is observed below the temperature of rare-earth subsystem ordering at relatively small critical fields of 5 kOe. This variety of spontaneous and induced phase transitions in RMn 2O 5 stems from the interplay of three magnetic subsystems: Mn 3+, Mn 4+, R 3+. The comparison with YMn 2O 5 highlights the role of rare earth in low-temperature region (metamagnetic and spin-reorientation phase transitions), while the phase transition at higher temperatures between incommensurate and commensurate phases should be ascribed to the different temperature dependences of Mn 3+ and Mn 4+ ions. The strong correlation of magnetoelastic and magnetoelectric properties observed in the whole class of RMn 2O 5 highlights their multiferroic nature.

  16. Quantitative Fissile Assay In Used Fuel Using LSDS System

    Directory of Open Access Journals (Sweden)

    Lee YongDeok

    2017-01-01

    Full Text Available A quantitative assay of isotopic fissile materials (U235, Pu239, Pu241 was done at Korea Atomic Energy Research Institute (KAERI, using lead slowing down spectrometer (LSDS. The optimum design of LSDS was performed based on economics, easy maintenance and assay effectiveness. LSDS system consists of spectrometer, neutron source, detection and control. LSDS system induces fissile fission and fast neutrons are collected at fission chamber. The detected signal has a direct relation to the mass of existing fissile isotopes. Many current commercial assay technologies have a limitation in direct application on isotopic fissile assay of spent fuel, except chemical analysis. In the designed system, the fissile assay model was setup and the correction factor for self-shield was obtained. The isotopic fissile content assay was performed by changing the content of Pu239. Based on the fuel rod, the isotopic content was consistent with ~2% uncertainty for Pu239. By applying the covering (neutron absorber, the effective shielding was obtained and the activation was calculated on the target. From the assay evaluation, LSDS technique is very powerful and direct to analyze the isotopic fissile content. LSDS is applicable for nuclear fuel cycle and spent fuel management for safety and economics. Additionally, an accurate fissile content will contribute to the international transparency and credibility on spent fuel.

  17. Quantitative Fissile Assay In Used Fuel Using LSDS System

    Science.gov (United States)

    Lee, YongDeok; Jeon, Ju Young; Park, Chang-Je

    2017-09-01

    A quantitative assay of isotopic fissile materials (U235, Pu239, Pu241) was done at Korea Atomic Energy Research Institute (KAERI), using lead slowing down spectrometer (LSDS). The optimum design of LSDS was performed based on economics, easy maintenance and assay effectiveness. LSDS system consists of spectrometer, neutron source, detection and control. LSDS system induces fissile fission and fast neutrons are collected at fission chamber. The detected signal has a direct relation to the mass of existing fissile isotopes. Many current commercial assay technologies have a limitation in direct application on isotopic fissile assay of spent fuel, except chemical analysis. In the designed system, the fissile assay model was setup and the correction factor for self-shield was obtained. The isotopic fissile content assay was performed by changing the content of Pu239. Based on the fuel rod, the isotopic content was consistent with 2% uncertainty for Pu239. By applying the covering (neutron absorber), the effective shielding was obtained and the activation was calculated on the target. From the assay evaluation, LSDS technique is very powerful and direct to analyze the isotopic fissile content. LSDS is applicable for nuclear fuel cycle and spent fuel management for safety and economics. Additionally, an accurate fissile content will contribute to the international transparency and credibility on spent fuel.

  18. Spontaneous reconnection at a separator current layer: 2. Nature of the waves and flows

    Science.gov (United States)

    Stevenson, J. E. H.; Parnell, C. E.

    2015-12-01

    Sudden destabilizations of the magnetic field, such as those caused by spontaneous reconnection, will produce waves and/or flows. Here we investigate the nature of the plasma motions resulting from spontaneous reconnection at a 3-D separator. In order to clearly see these perturbations, we start from a magnetohydrostatic equilibrium containing two oppositely signed null points joined by a generic separator along which lies a twisted current layer. The nature of the magnetic reconnection initiated in this equilibrium as a result of an anomalous diffusivity is discussed in detail in Stevenson and Parnell (2015). The resulting sudden loss of force balance inevitably generates waves that propagate away from the diffusion region carrying the dissipated current. In their wake a twisting stagnation flow, in planes perpendicular to the separator, feeds flux back into the original diffusion site (the separator) in order to try to regain equilibrium. This flow drives a phase of slow weak impulsive bursty reconnection that follows on after the initial fast-reconnection phase.

  19. Prompt neutron fission spectrum mean energies for the fissile nuclides and /sup 252/Cf

    Energy Technology Data Exchange (ETDEWEB)

    Holden, N.E.

    1985-01-01

    The international standard for a neutron spectrum is that produced from the spontaneous fission of /sup 252/Cf, while the thermal neutron induced fission neutron spectra for the four fissile nuclides, /sup 233/U, /sup 235/U, /sup 239/Pu, and /sup 241/Pu are of interest from the standpoint of nuclear reactors. The average neutron energies of these spectra are tabulated. The individual measurements are recorded with the neutron energy range measured, the method of detection as well as the average neutron energy for each author. Also tabulated are the measurements of the ratio of mean energies for pairs of fission neutron spectra. 75 refs., 9 tabs. (LEW)

  20. Fissile and non-fissile element separation in concrete radioactive waste drums using the SIMPHONIE method

    Energy Technology Data Exchange (ETDEWEB)

    Jallu, F. E-mail: fanny.jallu@cea.fr; Lyoussi, A.; Passard, C.; Payan, E.; Recroix, H.; Nurdin, G.; Buisson, A.; Allano, J

    2001-07-01

    The simultaneous photon and neutron interrogation experiment (SIMPHONIE) method, applied to radioactive waste drum characterization, has already been treated in [F. Jallu, A. Lyoussi, C. Passard, E. Payan, H. Recroix, G. Nurdin, A. Buisson, J. Allano, Nucl. Instr. and Meth. B 170 (2000) 489]. First experimental results carried out with U and Pu bare samples were presented, that showed the feasibility of quantifying fissile ({sup 235}U, {sup 239,241}Pu, ...) and non-fissile ({sup 234,236,238}U, {sup 238,240}Pu, ...) elements separately in only one measurement, using both active neutron interrogation and induced photofission interrogation techniques simultaneously. This paper presents new experimental results carried out with U samples embedded in a concrete matrix. These results have been obtained using the DGA/ETCA MiniLinatron pulsed linear electron accelerator located at Arcueil, France. Mass detection limits of less than 2 g of matter have been obtained with the preliminary setup used in these experiments.

  1. Fissile material disposition program: Screening of alternate immobilization candidates for disposition of surplus fissile materials

    Energy Technology Data Exchange (ETDEWEB)

    Gray, L.W.

    1996-01-08

    With the end of the Cold War, the world faces for the first time the need to dismantle vast numbers of ``excess`` nuclear weapons and dispose of the fissile materials they contain, together with fissile residues in the weapons production complex left over from the production of these weapons. If recently agreed US and Russian reductions are fully implemented, tens of thousands of nuclear weapons, containing a hundred tons or more of plutonium and hundreds of tonnes* of highly enriched uranium (HEU), will no longer be needed worldwide for military purposes. These two materials are the essential ingredients of nuclear weapons, and limits on access to them are the primary technical barrier to prospective proliferants who might desire to acquire a nuclear weapons capability. Theoretically, several kilograms of plutonium, or several times that amount of HEU, is sufficient to make a nuclear explosive device. Therefore, these materials will continue to be a potential threat to humanity for as long as they exist.

  2. Fission dynamics with systems of intermediate fissility

    Indian Academy of Sciences (India)

    E Vardaci; A Di Nitto; P N Nadtochy; A Brondi; G La Rana; R Moro; M Cinausero; G Prete; N Gelli; E M Kozulin; G N Knyazheva; I M Itkis

    2015-08-01

    A 4 light charged particle spectrometer, called 8 LP, is in operation at the Laboratori Nazionali di Legnaro, Italy, for studying reaction mechanisms in low-energy heavy-ion reactions. Besides about 300 telescopes to detect light charged particles, the spectrometer is also equipped with an anular PPAC system to detect evaporation residues and a two-arm time-of-flight spectrometer to detect fission fragments. The spectrometer has been used in several fission dynamics studies using as a probe light charged particles in the fission and evaporation residues (ER) channels. This paper proposes a journey within some open questions about the fission dynamics and a review of the main results concerning nuclear dissipation and fission time-scale obtained from several of these studies. In particular, the advantages of using systems of intermediate fissility will be discussed.

  3. γ-ray self-absorption of cylindrical fissile material

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong-Yi; CHENG Yi-Ying; TIAN Dong-Feng; LU Fu-Quan; YANG Fu-Jia

    2005-01-01

    The self-absorption of γ-ray emitted from cylindrical fissile materials, such as 235U and 239Pu, does not possess spherical symmetry. The analytical formulae of self-absorption for γ-ray throughout the cylinder have been obtained. The intensity of γ-ray is a function of γ-ray outgoing directions and cylindrical configurations, accordingly one can acquire the information about geometrical configuration of cylindrical fissile materials through multi-location measurements. Further more, the method is given in this article. The result can be applied to the fissile material safeguard, such as nuclear monitoring and verifying.

  4. DEVELOPMENT OF LEAD SLOWING DOWN SPECTROMETER FOR ISOTOPIC FISSILE ASSAY

    Directory of Open Access Journals (Sweden)

    SANG JOON AHN

    2014-12-01

    Full Text Available A lead slowing down spectrometer (LSDS is under development for analysis of isotopic fissile material contents in pyro-processed material, or spent fuel. Many current commercial fissile assay technologies have a limitation in accurate and direct assay of fissile content. However, LSDS is very sensitive in distinguishing fissile fission signals from each isotope. A neutron spectrum analysis was conducted in the spectrometer and the energy resolution was investigated from 0.1eV to 100keV. The spectrum was well shaped in the slowing down energy. The resolution was enough to obtain each fissile from 0.2eV to 1keV. The detector existence in the lead will disturb the source neutron spectrum. It causes a change in resolution and peak amplitude. The intense source neutron production was designed for ∼E12 n's/sec to overcome spent fuel background. The detection sensitivity of U238 and Th232 fission chamber was investigated. The first and second layer detectors increase detection efficiency. Thorium also has a threshold property to detect the fast fission neutrons from fissile fission. However, the detection of Th232 is about 76% of that of U238. A linear detection model was set up over the slowing down neutron energy to obtain each fissile material content. The isotopic fissile assay using LSDS is applicable for the optimum design of spent fuel storage to maximize burnup credit and quality assurance of the recycled nuclear material for safety and economics. LSDS technology will contribute to the transparency and credibility of pyro-process using spent fuel, as internationally demanded.

  5. DESIGN OF LSDS FOR ISOTOPIC FISSILE ASSAY IN SPENT FUEL

    Directory of Open Access Journals (Sweden)

    YONGDEOK LEE

    2013-12-01

    Full Text Available A future nuclear energy system is being developed at Korea Atomic Energy Research Institute (KAERI, the system involves a Sodium Fast Reactor (SFR linked with the pyro-process. The pyro-process produces a source material to fabricate a SFR fuel rod. Therefore, an isotopic fissile content assay is very important for fuel rod safety and SFR economics. A new technology for an analysis of isotopic fissile content has been proposed using a lead slowing down spectrometer (LSDS. The new technology has several features for a fissile analysis from spent fuel: direct isotopic fissile assay, no background interference, and no requirement from burnup history information. Several calculations were done on the designed spectrometer geometry: detection sensitivity, neutron energy spectrum analysis, neutron fission characteristics, self shielding analysis, and neutron production mechanism. The spectrum was well organized even at low neutron energy and the threshold fission chamber was a proper choice to get prompt fast fission neutrons. The characteristic fission signature was obtained in slowing down neutron energy from each fissile isotope. Another application of LSDS is for an optimum design of the spent fuel storage, maximization of the burnup credit and provision of the burnup code correction factor. Additionally, an isotopic fissile content assay will contribute to an increase in transparency and credibility for the utilization of spent fuel nuclear material, as internationally demanded.

  6. Natural induction of spontaneous liver steatosis in Greylag Landaise geese (Anser anser).

    Science.gov (United States)

    Guy, G; Fortun-Lamothe, L; Bénard, G; Fernandez, X

    2013-01-01

    The present experiment aimed at demonstrating that the Greylag geese (Anser anser), commonly used for the production of foie gras, are able to develop spontaneous hyperphagia and subsequent liver steatosis under specific handling conditions and without overfeeding. One hundred and eighty male geese were used in this experiment. After a period of feed restriction, at the age of 19 wk, corn was provided ad libitum. From wk 21 to 23, the daylight duration was progressively reduced from 10 to 7 h and kept as such until the end of the experiment (wk 31). Thirty birds were slaughtered at wk 19, 23, 25, 27, 29, and 31. During the first 2 wk after corn delivery, the average consumption rose up to 600 g/bird/d and decreased slowly thereafter to reach 270 g at wk 31. The liver weight increased from 95 (wk 19) to 514 g (wk 31), and most of these changes were due to the increase in liver lipid content from 6 to 50% of liver weight. There was no mortality during the experimental period. Histological observations indicate that the accumulation of fat in the livers occurred through a large increase in the size of the hepatocytes without modification of the cell boundaries and without any sign of inflammation or degeneration. Our data clearly show that under specific management conditions of feeding and photoperiod, the geese are able to initiate spontaneous liver steatosis. These results demonstrate their natural ability to store fat in the liver without any visible sign of tissue alteration. However, the variability in the response remains very high (at wk 31, the CV in liver weight was 45%). Further research is needed to better understand the origin of this variability.

  7. Reduced stathmin-1 expression in natural killer cells associated with spontaneous abortion.

    Science.gov (United States)

    Lin, Yi; Li, Cui; Shan, Bin; Wang, Wenjing; Saito, Shigeru; Xu, Jiehan; Di, Jingfang; Zhong, Yanmin; Li, Da-Jin

    2011-02-01

    Female CBA/J mice impregnated by male DBA/2J mice (CBA/J×DBA/2J matings) are prone to spontaneous abortion, although the reason for this is unclear. In this study, the stathmin-1 expression pattern was evaluated in uterine natural killer (uNK) cells purified from CBA/J×DBA/2J matings. Results were compared with those in a CBA/J×BALB/c control group that yields successful pregnancies. The mean ± SD percentage of stathmin-1(+) cells in the CD49b(+) uNK cell population was lower in CBA/J×DBA/2J mice (0.7% ± 0.4%) than in control CBA/J×BALB/c mice (4.9% ± 1.5%, P stathmin-1 level in uNK cells was lower in CBA/J×DBA/2J mice than in control mice using Western blot analysis. Co-localization of lectin from Dolichos biflorus agglutinin (DBA-lectin) and stathmin-1 was confirmed using multivision immunohistochemical analysis. The frequency of stathmin-1(+)DBA-lectin(+) cells was lower in CBA/J×DBA/2J mice than in CBA/J×BALB/c mice. A similar trend in the frequency of stathmin-1(+)CD56(+) cells was seen in patients with unexplained spontaneous abortion compared with normal early pregnancy. A neutralizing antibody against stathmin-1 further increased the percentage of embryo loss in CBA/J×DBA/2J matings. These results provide evidence that stathmin-1 expression in uNK cells at the maternal-fetal interface may help modulate uNK cell function and may be beneficial for a successful pregnancy.

  8. Severe acute syphilitic posterior placoid chorioretinitis with complete spontaneous resolution: The natural course

    Science.gov (United States)

    Franco, Mónica; Nogueira, Vanda

    2016-01-01

    Purpose: We report on a case of unilateral acute syphilitic posterior placoid chorioretinitis (ASPPC) with spontaneous resolution of the lesions, and discuss the role of an altered versus adequate immune response as the major pathogenic factor. Methods: We describe a case of acute loss of visual acuity (VA) in the left eye (LE) in a 55-year-old healthy man. Results: The patient presented with VA of 20/20 in the right eye (RE) and hand movements in the LE. Fundoscopy revealed a large yellowish placoid macular lesion with subretinal fluid in the LE, with no abnormalities detected in the RE. Fluorescein angiography showed early hypofluorescence with late staining in the affected area. The clinical findings progressed fast during the first week, with extension of the initial lesion outside the temporal retinal vascular arcades and the appearance of new lesions in the same eye. The patient abandoned the clinic for two weeks with no treatment. When observed again, VA of the LE had recovered to 20/20 and the lesions had completely resolved. Venereal disease research laboratory (VDRL) and fluorescent treponemal antibody absorption (FTA-ABS) tests results were positive and HIV antibody test titers negative. The diagnosis of ASPPC in the left eye was made. The patient accepted treatment with penicillin G only 45 days after the initial presentation. AV remained stable at 20/20 both eyes and no relapses of the lesions were observed during this period without therapy. The patient was followed for 3 months after treatment. He remained asymptomatic and the ophthalmic examination was unremarkable. Conclusions: The pathogenesis of ASPPC is still not understood. Our case showed a sequential pattern of the chorioretinal lesions, with initial aggravation and complete posterior spontaneous resolution, showing the natural course of the disease. These findings suggest the presence of an adequate ocular immune response in patients with ASPPC, not supporting the initially proposed

  9. Microsurgeon Hirudo medicinalis as a Natural Bioshuttle for Spontaneous Mass Vaccination against Influenza A Virus

    Directory of Open Access Journals (Sweden)

    Sajjad Khani

    2011-09-01

    Full Text Available Introduction: Recent report on existence of a stem region of hemagglutinin has arisen new hopes for vaccination of influenza A as it consist of a conserve fusion peptide shared across several influenza subtypes and can be targeted by human immune system. Methods: Given that traditional vaccination based on live attenuated viruses often fails to surpass such viral infection, a great deal of attention has been devoted to develop a safe yet efficient system for vaccination influenza A. We believe that a natural bioshuttle can be recruited for spontaneous mass vaccination. Results: Thus, here, we hypothesize that a bioengineered transgenic Hirudo medicinalis can be considered as an alive bioshuttle for in-situ vaccination against influenza A virus. By introducing the designated gene(s encoding the target fragment (i.e., stem region of hemagglutinin, this microsurgeon can act as a rapid microproducer of viral proteins for in-house mass vaccination through imparting the necessary proteins such as those, naturally presented in leech's saliva. Conclusion: This peculiar bioshuttle can be easily exploited as a medical modality choice at home resulting in greater patient compliance.

  10. Searches for superheavy elements in nature: Cosmic-ray nuclei; spontaneous fission

    Energy Technology Data Exchange (ETDEWEB)

    Ter-Akopian, G.M., E-mail: gurgen@jinr.ru; Dmitriev, S.N.

    2015-12-15

    There is little chance that superheavy nuclei with lifetimes of no less than 100 million years are present on the stability island discovered at present. Also, pessimistic are the results of estimates made about their nucleosynthesis in r-process. Nevertheless, the search for these nuclei in nature is justified in view of the fundamental importance of this topic. The first statistically significant data set was obtained by the LDEF Ultra-Heavy Cosmic-Ray Experiment, consisting of 35 tracks of actinide nuclei in galactic cosmic rays. Because of their exceptionally long exposure time in Galaxy, olivine crystals extracted from meteorites generate interest as detectors providing unique data regarding the nuclear composition of ancient cosmic rays. The contemporary searches for superheavy elements in the earth matter rely on knowledge obtained from chemical studies of artificially synthesized superheavy nuclei. New results finding out the chemical behavior of superheavy elements should be employed to obtain samples enriched in their homologues. The detection of rare spontaneous fission events and the technique of accelerator mass spectrometry are employed in these experiments.

  11. The neutron emission method for determination of fissile materials within the spent fuel equipment optimization

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Zaid, A. [Nuclear Research Center, Atomic Energy Authority, 13759- Cairo (Ethiopia); Pytel, K. [Atomic Energy Institute, Research Reactor Center, 05-400 Otwock-Swierk (Poland)

    1998-07-01

    A nondestructive assay method using neutron technique for determination of the fissile isotopes content along the irradiated fuel rods of MARIA reactor is presented. This method is based on detection of the fission neutrons emitted from external neutron source and multiplied by the fissile isotopes U-235, Pu-239, and Pu-241 within the fuel rod. Neutrons emitted from the spent fuel originate mainly from induced fission in the fissile material and source neutrons penetrating the fuel rod without interaction. Additionally, the neutrons from ({alpha}, n) reaction and spontaneous fission of actinide isotopes contribute in the total population of emitted ones. The method gives a chance to perform an experimental calibration of the equipment using two points: fresh fuel rod (maximum signal plus background) and its mock-up (background). The Monte Carlo code has been used for the geometrical simulation and optimization of the measuring equipment: neutron source, moderating container, collimator, and the neutron detector. The results of the calculation show that the moderating container of 30 cm length and 32 cm diameter and a collimator of 26 cm length, 6.8 cm width, and 2 cm height are the optimal configuration. With respect to the fission chamber position, the number of neutrons has been calculated as a function of distance from the fuel rod surface in the case of fresh fuel and its mock-up. The distance, at which the ratio of the signal to background has its maximum, has been found at 4.5 cm far from the outer surface of the fuel. (author)

  12. Severe acute syphilitic posterior placoid chorioretinitis with complete spontaneous resolution: The natural course

    Directory of Open Access Journals (Sweden)

    Franco, Mónica

    2016-02-01

    Full Text Available Purpose: We report on a case of unilateral acute syphilitic posterior placoid chorioretinitis (ASPPC with spontaneous resolution of the lesions, and discuss the role of an altered versus adequate immune response as the major pathogenic factor.Methods: We describe a case of acute loss of visual acuity (VA in the left eye (LE in a 55-year-old healthy man.Results: The patient presented with VA of 20/20 in the right eye (RE and hand movements in the LE. Fundoscopy revealed a large yellowish placoid macular lesion with subretinal fluid in the LE, with no abnormalities detected in the RE. Fluorescein angiography showed early hypofluorescence with late staining in the affected area. The clinical findings progressed fast during the first week, with extension of the initial lesion outside the temporal retinal vascular arcades and the appearance of new lesions in the same eye. The patient abandoned the clinic for two weeks with no treatment. When observed again, VA of the LE had recovered to 20/20 and the lesions had completely resolved. Venereal disease research laboratory (VDRL and fluorescent treponemal antibody absorption (FTA-ABS tests results were positive and HIV antibody test titers negative. The diagnosis of ASPPC in the left eye was made. The patient accepted treatment with penicillin G only 45 days after the initial presentation. AV remained stable at 20/20 both eyes and no relapses of the lesions were observed during this period without therapy. The patient was followed for 3 months after treatment. He remained asymptomatic and the ophthalmic examination was unremarkable. Conclusions: The pathogenesis of ASPPC is still not understood. Our case showed a sequential pattern of the chorioretinal lesions, with initial aggravation and complete posterior spontaneous resolution, showing the natural course of the disease. These findings suggest the presence of an adequate ocular immune response in patients with ASPPC, not supporting the initially

  13. Leo Szilard Lectureship Award: Fissile Materials: A Global Threat

    Science.gov (United States)

    Rajaraman, Ramamurti

    2014-03-01

    The world has built up a huge glut of Fissile Materials, posing a potentially devastating threat. While specialists in the field have been aware of this danger for a long time, it was only after President Obama organized the Nuclear Security Summit in 2010 that the attention of the world's political leadership was drawn to it. We will present here an introductory overview of Fissile materials - their definition, significance and their production facilities and stocks in different parts of the world. We will also mention some of the efforts being made to verifiably cap and reduce their stocks as well as the technical and political complications involved in the process.

  14. Feasibility of fissile mass assay of spent nuclear fuel using {sup 252}Cf-source-driven frequency-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mattingly, J.K.; Valentine, T.E.; Mihalczo, J.T.

    1996-10-01

    The feasibility was evaluated using MCNP-DSP, an analog Monte Carlo transport cod to simulate source-driven measurements. Models of an isolated Westinghouse 17x17 PWR fuel assembly in a 1500-ppM borated water storage pool were used. In the models, the fuel burnup profile was represented using seven axial burnup zones, each with isotopics estimated by the PDQ code. Four different fuel assemblies with average burnups from fresh to 32 GWd/MTU were modeled and analyzed. Analysis of the fuel assemblies was simulated by inducing fission in the fuel using a {sup 252}Cf source adjacent to the assembly and correlating source fissions with the response of a bank of {sup 3}He detectors adjacent to the assembly opposite the source. This analysis was performed at 7 different axial positions on each of the 4 assemblies, and the source-detector cross-spectrum signature was calculated for each of these 28 simulated measurements. The magnitude of the cross-spectrum signature follows a smooth upward trend with increasing fissile material ({sup 235}U and {sup 239}Pu) content, and the signature is independent of the concentration of spontaneously fissioning isotopes (e.g., {sup 244}Cm) and ({alpha},n) sources. Furthermore, the cross-spectrum signature is highly sensitive to changes in fissile material content. This feasibility study indicated that the signature would increase {similar_to}100% in response to an increase of only 0.1 g/cm{sup 3} of fissile material.

  15. Spontaneous breaking of flavor symmetry and naturalness of nearly degenerate neutrino masses and bi-maximal mixing

    Institute of Scientific and Technical Information of China (English)

    吴岳良

    2000-01-01

    The gauge model with SO(3)F flavor symmetry and three Higgs triplets is studied. We show how the intriguing nearly degenerate neutrino mass and bi-maximal mixing scenario comes out naturally after spontaneous breaking of the symmetry. The hierarchy between the neutrino mass-squared differences, which is needed for reconciling both solar and atmospheric neutrino data, naturally results from an approximate permutation symmetry. The model can also lead to interesting phenomena on lepton-flavor violations via the SO(3)F gauge interactions.

  16. 49 CFR 173.453 - Fissile materials-exceptions.

    Science.gov (United States)

    2010-10-01

    ... exceeding 0.002 percent of the mass of uranium, and with a minimum nitrogen to uranium atomic ratio (N/U) of... determining the required mass for solid nonfissile material. (c) Low concentrations of solid fissile material... required mass of solid nonfissile material. (d) Uranium enriched in uranium-235 to a maximum of 1...

  17. Spontaneous Muon Emission during Fission, a New Nuclear Radioactivity

    CERN Document Server

    Ion, D B; Ion-Mihai, Reveica

    2011-01-01

    In this paper the essential theoretical predictions for the nuclear muonic radioactivity are presented by using a special fission-like model similar with that used in description of the pionic emission during fission. Hence, a fission-like model for the muonic radioactivity takes into account the essential degree of freedom of the system: muon-fissility, muon-fission barrier height, etc. Using this model it was shown that most of the SHE-nuclei lie in the region where the muonic fissility parameters attain their limiting value X=1. Hence, the SHE-region is characterized by the absence of a classical barrier toward spontaneous muon and pion emissions. Numerical estimations on the yields for the natural muonic radioactivities of the transuranium elements as well numerical values for barrier heights are given only for even-even parent nuclei. Some experimental results from LCP-identification emission spectrum are reviewed. Also, the experimental results obtained by Khryachkov et al, using new spectrometer for in...

  18. Natural History of Helicobacter pylori Infection in Mexican Schoolchildren: Incidence and Spontaneous Clearance

    Science.gov (United States)

    Duque, Ximena; Vilchis, Jenny; Mera, Robertino; Trejo-Valdivia, Belem; Goodman, Karen J.; Mendoza, Maria-Eugenia; Navarro, Fabiola; Roque, Victoria; Moran, Segundo; Torres, Javier; Correa, Pelayo

    2013-01-01

    Objectives The aim of the present study was to estimate the incidence and spontaneous clearance rate of Helicobacter pylori infection and the effect of some variables on these outcomes in schoolchildren. Methods From May 2005 to December 2010, 718 schoolchildren enrolled in 3 public boarding schools in Mexico City participated in the follow-up. At the beginning of the study and every 6 months thereafter, breath samples were taken to detect H pylori infection; blood samples and anthropometric measurements were taken to evaluate nutritional status. Data on sociodemographic characteristics were collected. Results The prevalence of H pylori infection was 38%. The incidence rate was 6.36%/year. Schoolchildren with anemia or iron deficiency at the beginning of the study (who received iron supplements) showed a higher infection acquisition rate than those with normal iron nutritional status, hazard ratio (HR) 12.52 (95% confidence interval [CI] 4.01%–39.12%), P <0.001 and HR 2.05 (95% CI 1.09%–3.87%), P = 0.027, respectively. The spontaneous clearance rate of the infection was 4.74%/year. The spontaneous clearance rate was higher in children who had iron deficiency (who received iron supplements), HR 5.02 (95% CI 1.33%–18.99%), P = 0.017, compared with those with normal nutritional iron status. It was lower in schoolchildren with ≥2 siblings compared with schoolchildren with 1 or no siblings, HR 0.23 (95% CI 0.08%–0.63%), P = 0.004. Conclusions H pylori infection status is dynamic in schoolchildren. Variables related to health status and infection transmission, such as iron status and number of siblings, are important for the incidence and spontaneous clearance of H pylori infection. PMID:22227999

  19. Natural history of spontaneous aortic intramural hematoma progression: Six years follow-up with cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Zhao Lei

    2010-05-01

    Full Text Available Abstract We described a 6 years follow-up of a spontaneous aortic intramural hematoma (IMH with cardiovascular magnetic resonance (CMR examination. Since multiple factors may play roles in the natural history of IMH, the patient experienced the course of progression, which included hematoma absorption, ulcer-like lesion, aneurysm and limited dissection. The initial and follow-up CMR examination included 3D CE MRA and non-enhanced "bright blood" pulse sequence. The inherent advantage of outstanding contrast with plain scan, which shorten the scan time and avoid potential risk of contrast agent, might make the fast gradient echo sequence as an alternative method when following stable IMH.

  20. Gamma ray absorption of cylindrical fissile material with dual shields

    Institute of Scientific and Technical Information of China (English)

    WU Chen-Yan; TIAN Dong-Feng; CHENG Yi-Ying; HUANG Yong-Yi; LU Fu-Quan; YANG Fu-Jia

    2005-01-01

    This work analyzed the gamma ray attenuation effect from the self-absorption and shield attenuation perspectively. An exact mathematical equation was given for the geometric factor of the cylindrical fissile material with dual shields. In addition, several approximation approaches suitable for real situation were discussed, especially in the radial and axial directions of the cylinders, since the G-factors have simple forms. Then the space distribution patterns of the G-factor were analyzed based on numerical result and effective ways to solve the geometric information of the cylindrical fissile material, the radii and the heights, were deduced. This method was checked and verified by numerical calculation. Because of the efficiency of the method, it is ideal for application in real situations, such as nuclear safeguards, which demands speed of detection and accuracy of geometric analysis.

  1. Fissile material storage in the Oak Ridge Radiochemical Development Facility

    Energy Technology Data Exchange (ETDEWEB)

    Primm, R.T. III

    1993-08-01

    As a part of a Department of Energy review of Oak Ridge National Laboratory facilities, nuclear safety documentation for the Radiochemical Development Facility (Building 3019) was found to be inadequate. While calculations existed which established safe limits for the storage of fissile material, these calculations were not performed with verified/validated software nor were the results reported in the manner prescribed by applicable DOE orders and ORNL procedures. To address this deficiency, the operations conducted in Building 3019 were reviewed and conditions were compared to available critical experiment data. Applicable critical experiments were selected and multiplication factors were calculated. Subcritical limits were derived for each of three fissile materials (U-233, U-235, and Pu-239). One application of these limits was to certify the safety of a storage array which could contain any or all of the above nuclides at varying degrees of moderation. The studies presented are believed to fulfill most of the applicable regulatory requirements.

  2. Minimizing the fissile inventory of the molten salt fast reactor

    OpenAIRE

    Merle-Lucotte, E.; Heuer, D.; Allibert, M.; Doligez, X.; Ghetta, V.

    2009-01-01

    International audience; Molten salt reactors in the configurations presented here, called Molten Salt Fast Reactors (MSFR), have been selected for further studies by the Generation IV International Forum. These reactors may be operated in simplified and safe conditions in the Th/233U fuel cycle with fluoride salts. We present here the concept, before focusing on a possible optimization in term of minimization of the initial fissile inventory. Our studies demonstrate that an inventory of 233U ...

  3. Development of an Air Transport Type A Fissile Package

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, P.; Ebert, K.

    2011-07-13

    This paper presents the summary of testing by the Savannah River National Laboratory (SRNL) to support development of a light weight (<140 lbs) air transport qualified Type A Fissile Packaging. The package design incorporates features and materials specifically designed to minimize packaging weight. The light weight package is being designed to provide confinement to the contents when subjected to the normal and hypothetical conditions required of an air transportable Type A Fissile radioactive material shipping package. The objective of these tests was to provide design input to the final design for the LORX Type A Fissile Air Transport Packaging when subjected to the performance requirements of the drop, crush and puncture probe test of 10CFR71. The post test evaluation of the prototype packages indicates that all of the tested designs would satisfactorily confine the content within the packaging. The differences in the performance of the prototypes varied significantly depending on the core materials and their relative densities. Information gathered from these tests is being used to develop the final design for the Department of Homeland Security.

  4. The simultaneous neutron and photon interrogation method for fissile and non-fissile element separation in radioactive waste drums

    Energy Technology Data Exchange (ETDEWEB)

    Jallu, F. E-mail: fanny.jallu@cea.fr; Lyoussi, A.; Passard, C.; Payan, E.; Recroix, H.; Nurdin, G.; Buisson, A.; Allano, J

    2000-10-01

    Measuring {alpha}-emitters such as ({sup 234,235,236,238}U, {sup 238,239,240,242,244}Pu, {sup 237}Np, {sup 241,243}Am, ...), in solid radioactive waste allows us to quantify the {alpha}-activity in a drum and then to classify it. The simultaneous photon and neutron interrogation experiment (SIMPHONIE) method dealt with in this paper, combines both active neutron interrogation and induced photofission interrogation techniques simultaneously. Its purpose is to quantify fissile ({sup 235}U, {sup 239,241}Pu, ...) and non-fissile ({sup 236,238}U, {sup 238,240}Pu, ...) elements separately in only one measurement. This paper presents the principle of the method, the experimental setup, and the first experimental results obtained using the DGA/ETCA Linac and MiniLinatron pulsed linear electron accelerators located at Arcueil, France. First studies were carried out with U and Pu bare samples.

  5. Spontaneous gastro-pancreatic fistula - a hitherto unknown natural history of IPMN?

    Science.gov (United States)

    Rao, V; Sarkar, R; Smithies, A; Razack, A; Wedgwood, K

    2012-06-01

    Intraductal papillary mucinous neoplasm (IPMN) is a distinct group of benign pancreatic neoplasms often discovered incidentally on imaging. Apart from their malignant potential, little is known about their natural history as most are surgically resected. We report an unusual presentation and possible natural history of IPMN in a patient who refused surgery and hence was on regular follow up.

  6. Canyon transfer neutron absorber to fissile material ratio analysis. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Clemmons, J.S.

    1994-03-04

    Waste tank fissile material and non-fissile material estimates are used to evaluate criticality safety for the existing sludge inventory and batches of sludge sent to Extended Sludge Processing (ESP). This report documents the weight ratios of several non-fissile waste constituents to fissile waste constituents from canyon reprocessing waste streams. Weight ratios of Fe, Mn, Al, Mi, and U-238 to fissile material are calculated from monthly loss estimates from the F and H Canyon Low Heat Waste (LHW) and High Heat Waste (HHW) streams. The monthly weight ratios for Fe, Mn and U-238 are then compared to calculated minimum safe weight ratios. Documented minimum safe weight ratios for Al and Ni to fissile material are currently not available. Total mass data for the subject sludge constituents is provided along with scatter plots of the monthly weight ratios for each waste stream.

  7. Bleomycin/interleukin-12 electrochemogenetherapy for treating naturally occurring spontaneous neoplasms in dogs.

    Science.gov (United States)

    Reed, S D; Fulmer, A; Buckholz, J; Zhang, B; Cutrera, J; Shiomitsu, K; Li, S

    2010-08-01

    On the basis of superior outcomes from electrochemogenetherapy (ECGT) compared with electrochemotherapy in mice, we determined the efficacy of ECGT applied to spontaneous canine neoplasms. Intralesional bleomycin (BLM) and feline interleukin-12 DNA injection combined with translesional electroporation resulted in complete cure of two recurrent World Health Organization stage T(2b)N(0)M(0) oral squamous cell carcinomas (SCCs) and one T(2)N(0)M(0) acanthomatous ameloblastoma. Three remaining dogs, which had no other treatment options, had partial responses to ECGT; one had mandibular T(3b)N(2b)M(1) melanoma with pulmonary and lymph node metastases; one had cubital T(3)N(0)M(1) histiocytic sarcoma with spleen metastases; and one had soft palate T(3)N(0)M(0) fibrosarcoma. The melanoma dog had decrease in the size of the primary tumor before recrudescence and euthanasia. The histiocytic sarcoma dog had resolution of the primary tumor, but was euthanized because of metastases 4 months after the only treatment. The dog with T(3)N(0)M(0) fibrosarcoma had tumor regression with recrudescence. Treatment was associated with minimal side effects and was easy to perform, was associated with repair of bone lysis in cured dogs, improved quality of life for dogs with partial responses and extended overall survival time. ECGT seems to be a safe and resulted in complete responses in SCC and acanthomatous ameloblastoma.

  8. Spontaneous germline excision of Tol1, a DNA-based transposable element naturally occurring in the medaka fish genome.

    Science.gov (United States)

    Watanabe, Kohei; Koga, Hajime; Nakamura, Kodai; Fujita, Akiko; Hattori, Akimasa; Matsuda, Masaru; Koga, Akihiko

    2014-04-01

    DNA-based transposable elements are ubiquitous constituents of eukaryotic genomes. Vertebrates are, however, exceptional in that most of their DNA-based elements appear to be inactivated. The Tol1 element of the medaka fish, Oryzias latipes, is one of the few elements for which copies containing an undamaged gene have been found. Spontaneous transposition of this element in somatic cells has previously been demonstrated, but there is only indirect evidence for its germline transposition. Here, we show direct evidence of spontaneous excision in the germline. Tyrosinase is the key enzyme in melanin biosynthesis. In an albino laboratory strain of medaka fish, which is homozygous for a mutant tyrosinase gene in which a Tol1 copy is inserted, we identified de novo reversion mutations related to melanin pigmentation. The gamete-based reversion rate was as high as 0.4%. The revertant fish carried the tyrosinase gene from which the Tol1 copy had been excised. We previously reported the germline transposition of Tol2, another DNA-based element that is thought to be a recent invader of the medaka fish genome. Tol1 is an ancient resident of the genome. Our results indicate that even an old element can contribute to genetic variation in the host genome as a natural mutator.

  9. Strong spontaneous tumor neoantigen responses induced by a natural human carcinogen

    Science.gov (United States)

    Creaney, Jenette; Ma, Shaokang; Sneddon, Sophie A; Tourigny, Michelle R; Dick, Ian M; Leon, Justine S; Khong, Andrea; Fisher, Scott A; Lake, Richard A; Lesterhuis, W Joost; Nowak, Anna K; Leary, Shay; Watson, Mark W; Robinson, Bruce W

    2015-01-01

    A key to improving cancer immunotherapy will be the identification of tumor-specific “neoantigens” that arise from mutations and augment the resultant host immune response. In this study we identified single nucleotide variants (SNVs) by RNA sequencing of asbestos-induced murine mesothelioma cell lines AB1 and AB1-HA. Using the NetMHCpan 2.8 algorithm, the theoretical binding affinity of predicted peptides arising from high-confidence, exonic, non-synonymous SNVs was determined for the BALB/c strain. The immunoreactivity to 20 candidate mutation-carrying peptides of increased affinity and the corresponding wild-type peptides was determined using interferon-γ ELISPOT assays and lymphoid organs of non-manipulated tumor-bearing mice. A strong endogenous immune response was demonstrated to one of the candidate neoantigens, Uqcrc2; this response was detected in the draining lymph node and spleen. Antigen reactive cells were not detected in non-tumor bearing mice. The magnitude of the response to the Uqcrc2 neoantigen was similar to that of the strong influenza hemagglutinin antigen, a model tumor neoantigen. This work confirms that the approach of RNAseq plus peptide prediction and ELISPOT testing is sufficient to identify natural tumor neoantigens. PMID:26140232

  10. Spontaneous obliteration highlights the dynamic nature of cerebral arteriovenous malformations: A case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Su Lone Lim

    2016-01-01

    Conclusion: In our center′s 20-year experience of treatment of cerebral AVMs (approximately 600 cases, this is the only case that has been aborted due to spontaneous obliteration leading us to infer that the incidence of spontaneous AVM obliteration is <1%. Spontaneous obliteration of AVM is a rare but well-established phenomenon that bears testimony to the dynamics of this vascular disorder.

  11. Fusion-Fission Hybrid for Fissile Fuel Production without Processing

    Energy Technology Data Exchange (ETDEWEB)

    Fratoni, M; Moir, R W; Kramer, K J; Latkowski, J F; Meier, W R; Powers, J J

    2012-01-02

    Two scenarios are typically envisioned for thorium fuel cycles: 'open' cycles based on irradiation of {sup 232}Th and fission of {sup 233}U in situ without reprocessing or 'closed' cycles based on irradiation of {sup 232}Th followed by reprocessing, and recycling of {sup 233}U either in situ or in critical fission reactors. This study evaluates a third option based on the possibility of breeding fissile material in a fusion-fission hybrid reactor and burning the same fuel in a critical reactor without any reprocessing or reconditioning. This fuel cycle requires the hybrid and the critical reactor to use the same fuel form. TRISO particles embedded in carbon pebbles were selected as the preferred form of fuel and an inertial laser fusion system featuring a subcritical blanket was combined with critical pebble bed reactors, either gas-cooled or liquid-salt-cooled. The hybrid reactor was modeled based on the earlier, hybrid version of the LLNL Laser Inertial Fusion Energy (LIFE1) system, whereas the critical reactors were modeled according to the Pebble Bed Modular Reactor (PBMR) and the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) design. An extensive neutronic analysis was carried out for both the hybrid and the fission reactors in order to track the fuel composition at each stage of the fuel cycle and ultimately determine the plant support ratio, which has been defined as the ratio between the thermal power generated in fission reactors and the fusion power required to breed the fissile fuel burnt in these fission reactors. It was found that the maximum attainable plant support ratio for a thorium fuel cycle that employs neither enrichment nor reprocessing is about 2. This requires tuning the neutron energy towards high energy for breeding and towards thermal energy for burning. A high fuel loading in the pebbles allows a faster spectrum in the hybrid blanket; mixing dummy carbon pebbles with fuel pebbles enables a softer spectrum in

  12. TYPE A FISSILE PACKAGING FOR AIR TRANSPORT PROJECT OVERVIEW

    Energy Technology Data Exchange (ETDEWEB)

    Eberl, K.; Blanton, P.

    2013-10-11

    This paper presents the project status of the Model 9980, a new Type A fissile packaging for use in air transport. The Savannah River National Laboratory (SRNL) developed this new packaging to be a light weight (<150-lb), drum-style package and prepared a Safety Analysis for Packaging (SARP) for submission to the DOE/EM. The package design incorporates unique features and engineered materials specifically designed to minimize packaging weight and to be in compliance with 10CFR71 requirements. Prototypes were fabricated and tested to evaluate the design when subjected to Normal Conditions of Transport (NCT) and Hypothetical Accident Conditions (HAC). An overview of the design details, results of the regulatory testing, and lessons learned from the prototype fabrication for the 9980 will be presented.

  13. Examining the stability of thermally fissile Th and U isotopes

    Science.gov (United States)

    Kumar, Bharat; Biswal, S. K.; Singh, S. K.; Patra, S. K.

    2015-11-01

    The properties of recently predicted thermally fissile Th and U isotopes are studied within the framework of the relativistic mean-field approach using the axially deformed basis. We calculate the ground, first intrinsic excited state for highly neutron-rich thorium and uranium isotopes. The possible modes of decay such as α decay and β decay are analyzed. We found that neutron-rich isotopes are stable against α decay, however, they are very unstable against β decay. The lifetime of these nuclei is predicted to be tens of seconds against β decay. If these nuclei are utilized before their decay time, a lot of energy can be produced with the help of multifragmentation fission. Also, these nuclei have great implications from the astrophysical point of view. In some cases, we found that the isomeric states with energy range from 2 to 3 MeV and three maxima in the potential energy surface of Th-230228 and U-234228 isotopes.

  14. R&D plan for immobilization technologies: fissile materials disposition program. Revision 1.0

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, H.F.; Armantrout, G.A.

    1996-09-01

    In the aftermath of the Cold War, the US and Russia have agreed to large reductions in nuclear weapons. To aid in the selection of long- term fissile material management options, the Department of Energy`s Fissile Materials Disposition Program (FMDP) is conducting studies of options for the storage and disposition of surplus plutonium (Pu). One set of alternatives for disposition involve immobilization. The immobilization alternatives provide for fixing surplus fissile materials in a host matrix in order to create a solid disposal form that is nuclear criticality-safe, proliferation-resistant and environmentally acceptable for long-term storage or disposal.

  15. Operational Characteristics of an Accelerator Driven Fissile Solution System

    Energy Technology Data Exchange (ETDEWEB)

    Kimpland, Robert Herbert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-28

    Operational characteristics represent the set of responses that a nuclear system exhibits during normal operation. Operators rely on this behavior to assess the status of the system and to predict the consequences of off-normal events. These characteristics largely refer to the relationship between power and system operating conditions. The static and dynamic behavior of a chain-reacting system, operating at sufficient power, is primarily governed by reactivity effects. The science of reactor physics has identified and evaluated a number of such effects, including Doppler broadening and shifts in the thermal neutron spectrum. Often these reactivity effects are quantified in the form of feedback coefficients that serve as coupling coefficients relating the neutron population and the physical mechanisms that drive reactivity effects, such as fissile material temperature and density changes. The operational characteristics of such nuclear systems usually manifest themselves when perturbations between system power (neutron population) and system operating conditions arise. Successful operation of such systems require the establishment of steady equilibrium conditions. However, prior to obtaining the desired equilibrium (steady-state) conditions, an approach from zero-power (startup) must occur. This operational regime may possess certain limiting system conditions that must be maintained to achieve effective startup. Once steady-state is achieved, a key characteristic of this operational regime is the level of stability that the system possesses. Finally, a third operational regime, shutdown, may also possess limiting conditions of operation that must be maintained. This report documents the operational characteristics of a “generic” Accelerator Driven Fissile Solution (ADFS) system during the various operational regimes of startup, steady-state operation, and shutdown. Typical time-dependent behavior for each operational regime will be illustrated, and key system

  16. The Future of Nuclear Archaeology: Reducing Legacy Risks of Weapons Fissile Material

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Thomas W.; Reid, Bruce D.; Toomey, Christopher M.; Krishnaswami, Kannan; Burns, Kimberly A.; Casazza, Larry O.; S. Daly, Don; L. Duckworth, Leesa

    2014-01-01

    This report describes the value proposition for a "nuclear archeological" technical capability and applications program, targeted at resolving uncertainties regarding fissile materials production and use. At its heart, this proposition is that we can never be sure that all fissile material is adequately secure without a clear idea of what "all" means, and that uncertainty in this matter carries risk. We argue that this proposition is as valid today, under emerging state and possible non-state nuclear threats, as it was in an immediate post-Cold-War context, and describe how nuclear archeological methods can be used to verify fissile materials declarations, or estimate and characterize historical fissile materials production independently of declarations.

  17. Non-proliferation, safeguards, and security for the fissile materials disposition program immobilization alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Duggan, R.A.; Jaeger, C.D.; Tolk, K.M. [Sandia National Labs., Albuquerque, NM (United States); Moore, L.R. [Lawrence Livermore National Lab., CA (United States)

    1996-05-01

    The Department of Energy is analyzing long-term storage and disposition alternatives for surplus weapons-usable fissile materials. A number of different disposition alternatives are being considered. These include facilities for storage, conversion and stabilization of fissile materials, immobilization in glass or ceramic material, fabrication of fissile material into mixed oxide (MOX) fuel for reactors, use of reactor based technologies to convert material into spent fuel, and disposal of fissile material using geologic alternatives. This paper will focus on how the objectives of reducing security and proliferation risks are being considered, and the possible facility impacts. Some of the areas discussed in this paper include: (1) domestic and international safeguards requirements, (2) non-proliferation criteria and measures, (3) the threats, and (4) potential proliferation, safeguards, and security issues and impacts on the facilities. Issues applicable to all of the possible disposition alternatives will be discussed in this paper. However, particular attention is given to the plutonium immobilization alternatives.

  18. Extensions to Dynamic System Simulation of Fissile Solution Systems

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bernardin, John David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kimpland, Robert Herbert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Spernjak, Dusan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-24

    Previous reports have documented the results of applying dynamic system simulation (DSS) techniques to model a variety of fissile solution systems. The SUPO (Super Power) aqueous homogeneous reactor (AHR) was chosen as the benchmark for comparison of model results to experimental data for steadystate operation.1 Subsequently, DSS was applied to additional AHR to verify results obtained for SUPO and extend modeling to prompt critical excursions, ramp reactivity insertions of various magnitudes and rate, and boiling operations in SILENE and KEWB (Kinetic Experiment Water Boiler).2 Additional models for pressurized cores (HRE: Homogeneous Reactor Experiment), annular core geometries, and accelerator-driven subcritical systems (ADAHR) were developed and results reported.3 The focus of each of these models is core dynamics; neutron kinetics, thermal hydraulics, radiolytic gas generation and transport are coupled to examine the time-based evolution of these systems from start-up through transition to steady-state. A common characteristic of these models is the assumption that (a) core cooling system inlet temperature and flow and (b) plenum gas inlet pressure and flow are held constant; no external (to core) component operations that may result in dynamic change to these parameters are considered. This report discusses extension of models to include explicit reference to cooling structures and radiolytic gas handling. The accelerator-driven subcritical generic system model described in References 3 and 4 is used as a basis for this extension.

  19. Simulator for an Accelerator-Driven Subcritical Fissile Solution System

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Day, Christy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Determan, John C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-14

    LANL has developed a process to generate a progressive family of system models for a fissile solution system. This family includes a dynamic system simulation comprised of coupled nonlinear differential equations describing the time evolution of the system. Neutron kinetics, radiolytic gas generation and transport, and core thermal hydraulics are included in the DSS. Extensions to explicit operation of cooling loops and radiolytic gas handling are embedded in these systems as is a stability model. The DSS may then be converted to an implementation in Visual Studio to provide a design team the ability to rapidly estimate system performance impacts from a variety of design decisions. This provides a method to assist in optimization of the system design. Once design has been generated in some detail the C++ version of the system model may then be implemented in a LabVIEW user interface to evaluate operator controls and instrumentation and operator recognition and response to off-normal events. Taken as a set of system models the DSS, Visual Studio, and LabVIEW progression provides a comprehensive set of design support tools.

  20. Examining the stability of thermally fissile Th and U isotopes

    CERN Document Server

    Kumar, Bharat; Singh, S K; Patra, S K

    2015-01-01

    The properties of recently predicted thermally fissile Th and U isotopes are studied within the framework of relativistic mean field (RMF) approach using axially deformed basis. We calculated the ground, first intrinsic excited state and matter density for highly neutron-rich thorium and uranium isotopes. The possible modes of decay like $\\alpha$-decay and $\\beta$-decay are analyzed. We found that the neutron-rich isotopes are stable against $\\alpha$-decay, however they are very much unstable against $\\beta$-decay. The life time of these nuclei predicted to be tens of second against $\\beta$-decay. If these nuclei utilize before their decay time, a lots of energy can be produced within the help of multi-fragmentation fission. Also, these nuclei have a great implication in astrophysical point of view. The total nucleonic densities distribution are calculated, from which the clusters inside the parent nuclei are determined. %Most of the thorium isotopes are $\\alpha$ emitters, where as some %of them have short ha...

  1. Simulator for an Accelerator-Driven Subcritical Fissile Solution System

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Day, Christy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Determan, John C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-14

    LANL has developed a process to generate a progressive family of system models for a fissile solution system. This family includes a dynamic system simulation comprised of coupled nonlinear differential equations describing the time evolution of the system. Neutron kinetics, radiolytic gas generation and transport, and core thermal hydraulics are included in the DSS. Extensions to explicit operation of cooling loops and radiolytic gas handling are embedded in these systems as is a stability model. The DSS may then be converted to an implementation in Visual Studio to provide a design team the ability to rapidly estimate system performance impacts from a variety of design decisions. This provides a method to assist in optimization of the system design. Once design has been generated in some detail the C++ version of the system model may then be implemented in a LabVIEW user interface to evaluate operator controls and instrumentation and operator recognition and response to off-normal events. Taken as a set of system models the DSS, Visual Studio, and LabVIEW progression provides a comprehensive set of design support tools.

  2. Statistics vs. dynamics: hints from systems of intermediate fissility

    Energy Technology Data Exchange (ETDEWEB)

    Vardaci, E; Di Nitto, A; Brondi, A; Rana, G La; Moro, R [Dipartimento di Scienze Fisiche, Universita di Napoli ' Federico II' , 80126 Napoli (Italy); Nadtochy, P; Ordine, A; Boiano, A [Istituto Nazionale di Fisica Nucleare, 80126 Napoli (Italy); Cinausero, M; Prete, G; Rizzi, V [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Legnaro (Padova) (Italy); Gelli, N; Lucarelli, F [Dipartimento di Fisica and Istituto Nazionale di Fisica Nucleare, Firenze (Italy); Knyazheva, G N; Kozulin, E M; Loktev, T A; Smirnov, S, E-mail: Emanuele.Vardaci@na.infn.it [Flerov Laboratory of Nuclear Reactions, JINR, 141980, Dubna (Russian Federation)

    2011-02-01

    Systems of intermediate fissility are characterized by an evaporation residues cross section comparable or larger than the fission cross section, and by a relatively higher probability for charged particle emission in the pre-scission channel. In a theoretical framework in which time scale estimates of the fission process rely on statistical model calculations, the analysis of particle emission in the evaporation residues channel is the source of additional constraints on statistical and dynamical models. This contribution will focus on our statistical and dynamical analysis of a more complete set of data from the system {sup 32}S + {sup 100}Mo at E{sub Lab} = 200 MeV. Statistical model fails in reproducing the whole set of data and no convincing estimate is possible of the fission time scale. In particular, while pre-scission multiplicities can be reproduced without delay, the model strongly overestimates proton and alpha particle multiplicities in the evaporation residues channel irrespective of the statistical model input parameters and prescriptions used for the level density and the transmission coefficients. The analysis of the same set of data with a dynamical model produces a very good agreement with the full set of data and indicates that one-body dissipation plays a dominant role in the fission process, implying a fission delay of 23-25x10{sup -21}s.

  3. Blend Down Monitoring System Fissile Mass Flow Monitor Implementation at the ElectroChemical Plant, Zelenogorsk, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, T.

    2005-11-11

    The implementation plans and preparations for installation of the Fissile Mass Flow Monitor (FMFM) equipment at the ElectroChemical Plant (ECP), Zelenogorsk, Russia, are presented in this report. The FMFM, developed at Oak Ridge National Laboratory, is part of the Blend Down Monitoring System (BDMS), developed for the U.S. Department of Energy Highly Enriched Uranium (HEU) Transparency Implementation Program. The BDMS provides confidence to the United States that the Russian nuclear facilities supplying the lower-assay ({approx}4%) product low enriched uranium (P-LEU) to the United States from down-blended weapons-grade HEU are meeting the nonproliferation goals of the government-to-government HEU Purchase Agreement, signed between the Russian Federation and the United States in 1993. The first BDMS has been operational at Ural Electrochemical Integrated Plant, Novouralsk, since February 1999 and is successfully providing HEU transparency data to the United States. The second BDMS was installed at ECP in February 2003. The FMFM makes use of a set of thermalized californium-252 ({sup 252}Cf) spontaneous neutron sources for a modulated fission activation of the UF{sub 6} gas stream for measuring the {sup 235}U fissile mass flow rate. To do this, the FMFM measures the transport time of the fission fragments created from the fission activation process under the modulated source to the downstream detectors by detecting the delayed gamma rays from the fission fragments. The FMFM provides unattended, nonintrusive measurements of the {sup 235}U mass flow in the HEU, LEU blend stock, and P-LEU process legs. The FMFM also provides the traceability of the HEU flow to the product process leg. This report documents the technical installation requirements and the expected operational characteristics of the ECP FMFM.

  4. Vibrational spectroscopies: a natural ''mesoscope'' for the study of spontaneous ordering in alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chafi, Allal; Souhabi, Jihane; Pages, Olivier; Postnikov, Andrei; Gleize, Jerome [LPMD, Universite Paul Verlaine - Metz, 1 Bd Arago, 57078 Metz (France); Sallet, V. [GEMAC-CNRS, 1 Pl. Briand, 92195 Meudon (France); Li, L.H.; Harmand, J.C. [LPN-CNRS, Route de Nozay, 91460 Marcoussis (France)

    2009-05-15

    The novel paradigm of a 1-bond{yields}2-mode percolation-type behavior for the lattice dynamics at the zone-centre of random semiconductor alloys, that mirrors a lattice relaxation of the similar 1-bond{yields}2-length type, opens an attractive area for a (re-)discussion of spontaneous long-range clustering/anticlustering in terms of purely intrinsic effects. As examples, we show in this work how such antagonist effects as CuPt type spontaneous ordering of InGaP{sub 2} and N-induced In-anticlustering far from N-impurities in (N,In)-dilute InGaAsN can be discussed/evidenced from the transverse optical vibration spectra. The whole discussion is supported by full contour modelling of the TO Raman lineshapes via our percolation model. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. A Graphical Examination of Uranium and Plutonium Fissility

    Science.gov (United States)

    Reed, B. Cameron

    2008-01-01

    The issue of why only particular isotopes of uranium and plutonium are suitable for use in nuclear weapons is analyzed with the aid of graphs and semiquantitative discussions of parameters such as excitation energies, fission barriers, reaction cross-sections, and the role of processes such as [alpha]-decay and spontaneous fission. The goal is to…

  6. Temperature Profile of the Solution Vessel of an Accelerator-Driven Subcritical Fissile Solution System

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Determan, John C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-14

    Dynamic System Simulation (DSS) models of fissile solution systems have been developed and verified against a variety of historical configurations. DSS techniques have been applied specifically to subcritical accelerator-driven systems using fissile solution fuels of uranium. Initial DSS models were developed in DESIRE, a specialized simulation scripting language. In order to tailor the DSS models to specifically meet needs of system designers they were converted to a Visual Studio implementation, and one of these subsequently to National Instrument’s LabVIEW for human factors engineering and operator training. Specific operational characteristics of subcritical accelerator-driven systems have been examined using a DSS model tailored to this particular class using fissile fuel.

  7. Influence of asymmetry and fissility on even-odd effect in fission-fragment yields

    Directory of Open Access Journals (Sweden)

    Rejmund F.

    2010-10-01

    Full Text Available Based on a wide systematics of fragment distributions measured in thermal-neutron induced fission, the even-odd staggering in the fission-fragment element yields is investigated. The asymmetry evolution of the element yield distribution with the fissility of the fissioning nucleus is shown to be for an important part responsible for the decrease of the even-odd staggering with the fissility. The even-odd staggering close to symmetry is shown to be a small contribution to the global even-odd effect, and seems to vary little with the fissility of the nucleus. These experimental observations show that the established interpretation in which the intrinsic excitation energy at scission is accountable for the even-odd staggering amplitude has to be reconsidered.

  8. Temperature Profile of the Solution Vessel of an Accelerator-Driven Subcritical Fissile Solution System

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Determan, John C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-14

    Dynamic System Simulation (DSS) models of fissile solution systems have been developed and verified against a variety of historical configurations. DSS techniques have been applied specifically to subcritical accelerator-driven systems using fissile solution fuels of uranium. Initial DSS models were developed in DESIRE, a specialized simulation scripting language. In order to tailor the DSS models to specifically meet needs of system designers they were converted to a Visual Studio implementation, and one of these subsequently to National Instrument’s LabVIEW for human factors engineering and operator training. Specific operational characteristics of subcritical accelerator-driven systems have been examined using a DSS model tailored to this particular class using fissile fuel.

  9. 49 CFR 173.467 - Tests for demonstrating the ability of Type B and fissile materials packagings to withstand...

    Science.gov (United States)

    2010-10-01

    ... Type B and fissile materials packagings to withstand accident conditions in transportation. Each Type B packaging or packaging for fissile material must meet the test requirements prescribed in 10 CFR part 71 for... 49 Transportation 2 2010-10-01 2010-10-01 false Tests for demonstrating the ability of Type B...

  10. Blend Down Monitoring System Fissile Mass Flow Monitor and its Implementation at the Siberian Chemical Enterprise, Seversk, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, T

    2005-07-28

    In this paper the implementation plans and preparations for installation of the Fissile Mass Flow Monitor (FMFM) equipment at the Siberian Chemical Enterprise (SChE), Seversk, Russia, are presented. The FMFM, developed by Oak Ridge National Laboratory, is part of the Blend Down Monitoring System (BDMS) for the U.S. Department of Energy Highly Enriched Uranium (HEU) Transparency Implementation Program. The BDMS provides confidence to the United States that the Russian nuclear facilities supplying the lower assay ({approx}4%) product low enriched uranium (PLEU) to the United States from down-blended weapon-grade HEU are meeting the nonproliferation goals of the government-to-government HEU purchase agreement signed between the Russian Federation and the United States in 1993. The first BDMS has been operational at Ural Electrochemical Integrated Plant, Novouralsk, since February 1999. The second BDMS has been operational at Electro Chemical Plant, Zelenogorsk, since March 2003. These systems are successfully providing HEU transparency data to the United States. The third BDMS was successfully installed on the HEU down-blending tee in the SChE Enrichment Plant in October 2004. The FMFM makes use of a set of thermalized {sup 252}Cf spontaneous neutron sources for modulated fission activation of the UF{sub 6} gas stream for measuring the {sup 235}U fissile mass flow rate. To do this, the FMFM measures the transport time of the fission fragments created from the fission activation process under the modulated source to the downstream detectors by detecting the delayed gamma rays from the fission fragments retained in the flow. The FMFM provides unattended nonintrusive measurements of the {sup 235}U mass flow of the UF{sub 6} gas in the blending tee legs of HEU, the LEU blend stock, and the resulting P-LEU. The FMFM also confirms that highly enriched UF{sub 6} gas identified in the HEU leg flows through the blending tee into the P-LEU leg. This report contains details of

  11. Spontaneously fermented millet product as a natural probiotic treatment for diarrhoea in young children: an intervention study in Northern Ghana.

    Science.gov (United States)

    Lei, Vicki; Friis, Henrik; Michaelsen, Kim Fleischer

    2006-08-01

    Indigenous lactic acid fermented foods may have potential as probiotic treatment for diarrhoea, due to high levels of lactic acid bacteria. In this study the effect of a millet drink, spontaneously fermented by lactic acid bacteria, as a therapeutic agent among Ghanaian children with diarrhoea, was assessed. Children below 5 years of age coming to Northern Ghana health clinics for treatment of diarrhoea were randomised to two groups. Children of both groups received treatment for diarrhoea given at the local clinic. The intervention group in addition received up to 300 ml fermented millet drink (KSW) daily for 5 days after enrolment. The clinical outcome of diarrhoea and reported well-being were registered every day for the 5-day intervention and again 14 days after diagnosis. Among 184 children (mean age 17.4, standard deviation 11.3 months) included, no effects of the intervention were found with respect to stool frequency, stool consistency and duration of diarrhoea. However, KSW was associated with greater reported well-being 14 days after the start of the intervention (P=0.02). The fact that no effect of KSW on diarrhoea was observed could be because many children had a mild form of diarrhoea, and many were treated with antibiotics. Either this could have affected the lactic acid bacteria, or the lactic acid bacteria in KSW had no probiotic effects. It is speculated that the effect after two weeks could be due to a preventing effect of KSW on antibiotic-associated diarrhoea which could help reducing persistent diarrhoea.

  12. Spontaneous pneumothorax

    Directory of Open Access Journals (Sweden)

    Davari R

    1996-07-01

    Full Text Available A case with bilateral spontaneous pneumothorax was presented. Etiology, mechanism, and treatment were discussed on the review of literature. Spontaneous Pneumothorax is a clinical entity resulting from a sudden non traumatic rupture of the lung. Biach reported in 1880 that 78% of 916 patients with spontaneous pneumothorax had tuberculosis. Kjergaard emphasized 1932 the primary importance of subpleural bleb disease. Currently the clinical spectrum of spontaneous pneumothorax seems to have entered a third era with the recognition of the interstitial lung disease and AIDS as a significant etiology. Standard treatment is including: observation, thoracocentesis, tube thoracostomy. Chemical pleurodesis, bullectomy or wedge resection of lung with pleural abrasion and occasionally pleurectomy. Little information has been reported regarding the efficacy of such treatment in spontaneous pneumothorax secondary to non bleb disease

  13. Assessment and recommendations for fissile-material packaging exemptions and general licenses within 10 CFR Part 71

    Energy Technology Data Exchange (ETDEWEB)

    Parks, C.V.; Hopper, C.M.; Lichtenwalter, J.L. [Oak Ridge National Lab., TN (United States)

    1998-07-01

    This report provides a technical and regulatory assessment of the fissile material general licenses and fissile material exemptions within Title 10 of the Code of Federal Regulations Part 71. The assessment included literature studies and calculational analyses to evaluate the technical criteria; review of current industry practice and concerns; and a detailed evaluation of the regulatory text for clarity, consistency and relevance. Recommendations for potential consideration by the Nuclear Regulatory Commission staff are provided. The recommendations call for a simplification and consolidation of the general licenses and a change in the technical criteria for the first fissile material exemptions.

  14. Fissile materials in solution concentration measured by active neutron interrogation; Mesure de concentration en matiere fissile dans les liquides par interrogation neutronique active

    Energy Technology Data Exchange (ETDEWEB)

    Romeyer Dherbey, J.; Passard, Ch.; Cloue, J.; Bignan, G.

    1993-12-31

    The use of the active neutron interrogation to measure the concentration of plutonium contained in flow solutions is particularly interesting for fuel reprocessing plants. Indeed, this method gives a signal which is in a direct relation with the fissile materials concentration. Moreover, it is less sensitive to the gamma dose rate than the other nondestructive methods. Two measure methods have been evolved in CEA. Their principles are given into details in this work. The first one consists to detect fission delayed neutrons induced by a {sup 252} Cf source. In the second one fission prompt neutrons induced by a neutron generator of 14 MeV are detected. (O.M.). 6 refs.

  15. Genetic Basis for Spontaneous Hybrid Genome Doubling during Allopolyploid Speciation of Common Wheat Shown by Natural Variation Analyses of the Paternal Species

    Science.gov (United States)

    Matsuoka, Yoshihiro; Nasuda, Shuhei; Ashida, Yasuyo; Nitta, Miyuki; Tsujimoto, Hisashi; Takumi, Shigeo; Kawahara, Taihachi

    2013-01-01

    The complex process of allopolyploid speciation includes various mechanisms ranging from species crosses and hybrid genome doubling to genome alterations and the establishment of new allopolyploids as persisting natural entities. Currently, little is known about the genetic mechanisms that underlie hybrid genome doubling, despite the fact that natural allopolyploid formation is highly dependent on this phenomenon. We examined the genetic basis for the spontaneous genome doubling of triploid F1 hybrids between the direct ancestors of allohexaploid common wheat (Triticum aestivum L., AABBDD genome), namely Triticumturgidum L. (AABB genome) and Aegilopstauschii Coss. (DD genome). An Ae. tauschii intraspecific lineage that is closely related to the D genome of common wheat was identified by population-based analysis. Two representative accessions, one that produces a high-genome-doubling-frequency hybrid when crossed with a T. turgidum cultivar and the other that produces a low-genome-doubling-frequency hybrid with the same cultivar, were chosen from that lineage for further analyses. A series of investigations including fertility analysis, immunostaining, and quantitative trait locus (QTL) analysis showed that (1) production of functional unreduced gametes through nonreductional meiosis is an early step key to successful hybrid genome doubling, (2) first division restitution is one of the cytological mechanisms that cause meiotic nonreduction during the production of functional male unreduced gametes, and (3) six QTLs in the Ae. tauschii genome, most of which likely regulate nonreductional meiosis and its subsequent gamete production processes, are involved in hybrid genome doubling. Interlineage comparisons of Ae. tauschii’s ability to cause hybrid genome doubling suggested an evolutionary model for the natural variation pattern of the trait in which non-deleterious mutations in six QTLs may have important roles. The findings of this study demonstrated that the

  16. Recognition of tumor antigens in 4T1 cells by natural IgM from three strains of mice with different susceptibilities to spontaneous breast cancer

    Science.gov (United States)

    Díaz-Zaragoza, Mariana; Hernández-Ávila, Ricardo; Ostoa-Saloma, Pedro

    2017-01-01

    The issue of antibody responses to tumors is potentially important to cancer immunologists. Early detection of cancer represents one of the most promising approaches to reduce the growing cancer burden. Natural immunoglobulin (Ig)M antibodies have been associated with the recognition and elimination of cancerous and precancerous cells. Using natural IgM antibodies, the present study identified a set of antigens in healthy mice from three different strains and examined whether the global patterns of antibodies are able to discriminate between a condition of more or less susceptibility to breast cancer. The current study performed two-dimensional (2D) immunoblotting to detect antigens from 4T1 cells using natural IgM from serum of healthy female mice from three different strains. The t-test was used to analyze the total number of spots. There were no significant differences in the numbers of antigens recognized in each strain. However, differences in patterns were observed on 2D immunoblots among the three strains. The reactivity patterns of natural IgM antibodies to particular antigens exhibited non-random clustering, which discriminated between strains with different susceptibilities to spontaneous breast cancer. The results demonstrated that the patterns of reactivity to defined subsets of antigens are able to provide information regarding differential diagnosis associated with breast cancer sensitivity. Therefore, it may be concluded that it is possible to segregate the IgM humoral immune response toward cancer antigens according to the genetic background of individuals. In addition, it is possible to identify the recognized antigens that allow grouping or discriminate between the different IgM antibodies expressed. The possible association between a particular antigen and cancer susceptibility requires further study, but the methodology exposed in the present study may identify potential candidates for this possible association.

  17. Genetic basis for spontaneous hybrid genome doubling during allopolyploid speciation of common wheat shown by natural variation analyses of the paternal species.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Matsuoka

    Full Text Available The complex process of allopolyploid speciation includes various mechanisms ranging from species crosses and hybrid genome doubling to genome alterations and the establishment of new allopolyploids as persisting natural entities. Currently, little is known about the genetic mechanisms that underlie hybrid genome doubling, despite the fact that natural allopolyploid formation is highly dependent on this phenomenon. We examined the genetic basis for the spontaneous genome doubling of triploid F1 hybrids between the direct ancestors of allohexaploid common wheat (Triticum aestivum L., AABBDD genome, namely Triticumturgidum L. (AABB genome and Aegilopstauschii Coss. (DD genome. An Ae. tauschii intraspecific lineage that is closely related to the D genome of common wheat was identified by population-based analysis. Two representative accessions, one that produces a high-genome-doubling-frequency hybrid when crossed with a T. turgidum cultivar and the other that produces a low-genome-doubling-frequency hybrid with the same cultivar, were chosen from that lineage for further analyses. A series of investigations including fertility analysis, immunostaining, and quantitative trait locus (QTL analysis showed that (1 production of functional unreduced gametes through nonreductional meiosis is an early step key to successful hybrid genome doubling, (2 first division restitution is one of the cytological mechanisms that cause meiotic nonreduction during the production of functional male unreduced gametes, and (3 six QTLs in the Ae. tauschii genome, most of which likely regulate nonreductional meiosis and its subsequent gamete production processes, are involved in hybrid genome doubling. Interlineage comparisons of Ae. tauschii's ability to cause hybrid genome doubling suggested an evolutionary model for the natural variation pattern of the trait in which non-deleterious mutations in six QTLs may have important roles. The findings of this study demonstrated

  18. PETROGRAPHY AND APPLICATION OF THE RIETVELD METHOD TO THE QUANTITATIVE ANALYSIS OF PHASES OF NATURAL CLINKER GENERATED BY COAL SPONTANEOUS COMBUSTION

    Directory of Open Access Journals (Sweden)

    Pinilla A. Jesús Andelfo

    2010-06-01

    Full Text Available

    Fine-grained and mainly reddish color, compact and slightly breccious and vesicular pyrometamorphic rocks (natural clinker are associated to the spontaneous combustion of coal seams of the Cerrejón Formation exploited by Carbones del Cerrejón Limited in La Guajira Peninsula (Caribbean Region of Colombia. These rocks constitute remaining inorganic materials derived from claystones, mudstones and sandstones originally associated with the coal and are essentially a complex mixture of various amorphous and crystalline inorganic constituents. In this paper, a petrographic characterization of natural clinker, aswell as the application of the X-ray diffraction (Rietveld method by mean of quantitative analysis of its mineral phases were carried out. The RIQAS program was used for the refinement of X ray powder diffraction profiles, analyzing the importance of using the correct isostructural models for each of the existing phases, which were obtained from the Inorganic Crystal Structure Database (ICSD. The results obtained in this investigation show that the Rietveld method can be used as a powerful tool in the quantitative analysis of phases in polycrystalline samples, which has been a traditional problem in geology.

  19. The Rate and Spectrum of Spontaneous Mutations in Mycobacterium smegmatis, a Bacterium Naturally Devoid of the Postreplicative Mismatch Repair Pathway

    Directory of Open Access Journals (Sweden)

    Sibel Kucukyildirim

    2016-07-01

    Full Text Available Mycobacterium smegmatis is a bacterium that is naturally devoid of known postreplicative DNA mismatch repair (MMR homologs, mutS and mutL, providing an opportunity to investigate how the mutation rate and spectrum has evolved in the absence of a highly conserved primary repair pathway. Mutation accumulation experiments of M. smegmatis yielded a base-substitution mutation rate of 5.27 × 10−10 per site per generation, or 0.0036 per genome per generation, which is surprisingly similar to the mutation rate in MMR-functional unicellular organisms. Transitions were found more frequently than transversions, with the A:T→G:C transition rate significantly higher than the G:C→A:T transition rate, opposite to what is observed in most studied bacteria. We also found that the transition-mutation rate of M. smegmatis is significantly lower than that of other naturally MMR-devoid or MMR-knockout organisms. Two possible candidates that could be responsible for maintaining high DNA fidelity in this MMR-deficient organism are the ancestral-like DNA polymerase DnaE1, which contains a highly efficient DNA proofreading histidinol phosphatase (PHP domain, and/or the existence of a uracil-DNA glycosylase B (UdgB homolog that might protect the GC-rich M. smegmatis genome against DNA damage arising from oxidation or deamination. Our results suggest that M. smegmatis has a noncanonical Dam (DNA adenine methylase methylation system, with target motifs differing from those previously reported. The mutation features of M. smegmatis provide further evidence that genomes harbor alternative routes for improving replication fidelity, even in the absence of major repair pathways.

  20. Fissile Nuclei Rotation Effect in 235U(n,γf) Process

    Science.gov (United States)

    Danilyan, Gevorg; Granz, Peter; Klenke, Jens; Krakhotin, Vyacheslav; Kuznetsov, Valery; Mezei, Ferenz; Novitsky, Vadim; Pavlov, Valery; Russina, Margarita; Shatalov, Pavel; Wilpert, Thomas

    2009-01-01

    A small shift of an angular distribution of prompt γ-rays relative to the fission axis of 236U* 235U(n,γf) process is presented. This effect has been observed in the experiment at BER-II reactor of BENSC/HMI (Berlin). The sign of the shift depends on the direction of the incident neutron beam polarization. This phenomena can be explained by the rotation of fissile nucleus 236U*, like the effect that has been observed recently at ILL in ternary fission of 235U by cold polarized neutrons. The main surprise of this result is the detection of scission gamma-rays radiated by a fissile nucleus during the time interval of the order of 10-21 s before or after the moment of the neck rupture. Detailed measurements of trigger γ-rays energy dependence are in progress at the neutron beam "MEPHISTO" of FRM-II reactor (Garching).

  1. Measuring of fissile isotopes partial antineutrino spectra in direct experiment at nuclear reactor

    CERN Document Server

    Sinev, V V

    2009-01-01

    The direct measuring method is considered to get nuclear reactor antineutrino spectrum. We suppose to isolate partial spectra of the fissile isotopes by using the method of antineutrino spectrum extraction from the inverse beta decay positron spectrum applied at Rovno experiment. This admits to increase the accuracy of partial antineutrino spectra forming the total nuclear reactor spectrum. It is important for the analysis of the reactor core fuel composition and could be applied for non-proliferation purposes.

  2. Basic Research on Remote Sensing of Fissile Materials utilizing Gamma rays and Neutrons

    Science.gov (United States)

    2017-02-01

    6201 Fort Belvoir, VA 22060-6201 T E C H N IC A L R E P O R T DTRA-TR-15-56 Basic Research on Remote Sensing of Fissile Materials...2017 HDTRA1-09-1-0059 David C. Ingram Prepared by: Ohio University 105 Research and Technology Center Athens, OH...AVAILABILITY STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION

  3. LANL's Role in the U.S. Fissile Material Disposition Program

    Energy Technology Data Exchange (ETDEWEB)

    Whitworth, Julia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kay, Virginia [NA-233

    2015-02-18

    The process of Fissile Material Disposition is in part a result of the Advanced Recovery and Integrated Extraction System (ARIES), which is an agreement between the U.S. and Russia to dispose of excess plutonium used to make weapons. LANL is one sight that aides in the process of dismantling, storage and repurposing of the plutonium gathered from dismantled weapons. Some uses for the repurposed plutonium is fuel for commercial nuclear reactors which will provide energy for citizens.

  4. Spontaneous focal activation of invariant natural killer T (iNKT cells in mouse liver and kidney

    Directory of Open Access Journals (Sweden)

    Zeng Jia

    2010-11-01

    Full Text Available Abstract Background Invariant natural killer T (iNKT cells differ from other T cells by their hyperactive effector T-cell status, in addition to the expression of NK lineage receptors and semi-invariant T-cell receptors. It is generally agreed that the immune phenotype of iNKT cells is maintained by repeated activation in peripheral tissues although no explicit evidence for such iNKT cell activity in vivo has so far been reported. Results We used an interferon (IFN-γ-inducible cytoplasmic protein, Irga6, as a histological marker for local IFN-γ production. Irga6 was intensely expressed in small foci of liver parenchymal cells and kidney tubular epithelium. Focal Irga6 expression was unaffected by germ-free status or loss of TLR signalling and was totally dependent on IFN-γ secreted by T cells in the centres of expression foci. These were shown to be iNKT cells by diagnostic T cell receptor usage and their activity was lost in both CD1 d and Jα-deficient mice. Conclusions This is the first report that supplies direct evidence for explicit activation events of NKT cells in vivo and raises issues about the triggering mechanism and consequences for immune functions in liver and kidney.

  5. Neutron multiplication method for measuring the amount of fissile isotopes in the spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Chwaszczewski, S.; Pytel, K. [Institute of Atomic Energy, 05-400 Otwock-Swierk (Poland); Abou-Zaid, A.A. [Atomic Energy Authority, 13759 Cairo (Egypt)

    2001-07-01

    A nondestructive assay method for determination the amount of fissile materials content along the vertical axis of irradiated fuel is presented. The method, called neutron multiplication method, can be realized as passive measurement technique and the active one. The Monte Carlo code has been used for the neutron transport simulation and optimization of the measuring equipment geometry. On the basis of these results, a preliminary experimental stand for MARIA reactor fuel investigation has been designed and the measurements have been performed for the fresh fuel and the fuel mock-up. Based upon both numerical and experimental simulations, an ultimate measuring stand has been designed and the measurements for MARIA spent fuel assemblies as well as for the fresh fuel and mock-up of the fuel have been carried out. The results showed that the active neutron technique does not provide sufficient resolution of the distribution of the amount of fissile materials. But rather can be applied for measurement of the absolute value. The passive one can be used to restore the distribution of the bum-up and the amount of fissile materials along the axial length of the spent fuel assembly. (author)

  6. Verification of a Fissile Material Cut-off Treaty (FMCT): The Potential Role of the IAEA

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Jin Ho [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

    2016-05-15

    The objective of a future verification of a FMCT(Fissile Material Cut-off Treaty) is to deter and detect non-compliance with treaty obligations in a timely and non-discriminatory manner with regard to banning the production of fissile material for nuclear weapons or other nuclear devices. Since the International Atomic Energy Agency (IAEA) has already established the IAEA safeguards as a verification system mainly for Non -Nuclear Weapon States (NNWSs), it is expected that the IAEA's experience and expertise in this field will make a significant contribution to setting up a future treaty's verification regime. This paper is designed to explore the potential role of the IAEA in verifying the future treaty by analyzing verification abilities of the Agency in terms of treaty verification and expected challenges. Furthermore, the concept of multilateral verification that could be facilitated by the IAEA will be examined as a measure of providing a credible assurance of compliance with a future treaty. In this circumstance, it is necessary for the IAEA to be prepared for playing a leading role in FMCT verifications as a form of multilateral verification by taking advantage of its existing verification concepts, methods, and tools. Also, several challenges that the Agency faces today need to be overcome, including dealing with sensitive and proliferative information, attribution of fissile materials, lack of verification experience in military fuel cycle facilities, and different attitude and culture towards verification between NWSs and NNWSs.

  7. Fissile material holdup measurement systems: an historical review of hardware and software

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Jeffrey Allen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Smith, Steven E [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rowe, Nathan C [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    The measurement of fissile material holdup is accomplished by passively measuring the energy-dependent photon flux and/or passive neutron flux emitted from the fissile material deposited within an engineered process system. Both measurement modalities--photon and neutron--require the implementation of portable, battery-operated systems that are transported, by hand, from one measurement location to another. Because of this portability requirement, gamma-ray spectrometers are typically limited to inorganic scintillators, coupled to photomultiplier tubes, a small multi-channel analyzer, and a handheld computer for data logging. For neutron detection, polyethylene-moderated, cadmium-back-shielded He-3 thermal neutron detectors are used, coupled to nuclear electronics for supplying high voltage to the detector, and amplifying the signal chain to the scaler for counting. Holdup measurement methods, including the concept of Generalized Geometry Holdup (GGH), are well presented by T. Douglas Reilly in LA-UR-07-5149 and P. Russo in LA-14206, yet both publications leave much of the evolutionary hardware and software to the imagination of the reader. This paper presents an historical review of systems that have been developed and implemented since the mid-1980s for the nondestructive assay of fissile material, in situ. Specifications for the next-generation holdup measurements systems are conjectured.

  8. Implementation of the Fissile Mass Flow Monitor Source Verification and Confirmation

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, Taner [ORNL; March-Leuba, Jose A [ORNL; Powell, Danny H [ORNL; Nelson, Dennis [Sandia National Laboratories (SNL); Radev, Radoslav [Lawrence Livermore National Laboratory (LLNL)

    2007-12-01

    This report presents the verification procedure for neutron sources installed in U.S. Department of Energy equipment used to measure fissile material flow. The Fissile Mass Flow Monitor (FMFM) equipment determines the {sup 235}U fissile mass flow of UF{sub 6} gas streams by using {sup 252}Cf neutron sources for fission activation of the UF{sub 6} gas and by measuring the fission products in the flow. The {sup 252}Cf sources in each FMFM are typically replaced every 2 to 3 years due to their relatively short half-life ({approx} 2.65 years). During installation of the new FMFM sources, the source identity and neutronic characteristics provided by the manufacturer are verified with the following equipment: (1) a remote-control video television (RCTV) camera monitoring system is used to confirm the source identity, and (2) a neutron detection system (NDS) is used for source-strength confirmation. Use of the RCTV and NDS permits remote monitoring of the source replacement process and eliminates unnecessary radiation exposure. The RCTV, NDS, and the confirmation process are described in detail in this report.

  9. DOE NCSP Review of TRUPACT-II/HalfPACT Fissile Limits

    Energy Technology Data Exchange (ETDEWEB)

    Goluoglu, S.

    2002-03-28

    The U.S. Department of Energy (DOE) Environmental Management (EM) Office of Nuclear Material & Spent Fuel, EM-21, tasked the CSSG to perform a scoping study to determine the feasibility of increasing the fissile mass loading limits for specified TRUPACT-II and HalfPACT packages and containers. The results of the scoping study may provide insights and technical guidance for establishing fissile mass loading limits at waste generator sites and at the waste repository. The goal is to reduce costs of transporting fissile material to the WIPP from EM's various closure sites. This report documents the results of the scoping study and demonstrates that it is feasible to significantly increase the fissile mass loading limits in the TRUPACT-II and HalfPACT packages and containers. Depending upon the particular payload containers used, the number of shipments to WIPP could be reduced by at least a factor of 2 and as much as a factor of 16 and the number of total payload containers required ''down-hole'' at WIPP could be reduced by at least a factor of 2 and as much as about 6. These cost savings result simply from applying a more realistic criticality analysis model rather than the very conservative, hypothetical, bounding analysis used to support the existing fissile mass loading limits. However, the applications of existing and developmental computational tools, nuclear data, and experiments from the DOE Nuclear Criticality Safety Program have the potential to further reduce transportation and disposal container costs on the order of 7% to 17%. It is suggested that EM proceed with an effort to do the required formal analyses and pursue SARP supplements to take advantage of these savings. The success of these analyses are dependent upon the availability of the majority of the infrastructure supported by the DOE Nuclear Criticality Safety Program as defined in the Five-Year Plan for the program. Finally, it should be noted that these potential cost

  10. Hume without Spontaneous Order

    Directory of Open Access Journals (Sweden)

    John Salter

    2015-01-01

    Full Text Available The question whether it is possible to be both a Humean and a contractarian arises from the interpretation of Hume as a theorist of spontaneous order, a theory that is usually taken to be incompatible with contractarianism. I argue that this interpretation is unconvincing and anachronistic. The real reason why it is problematic to view Hume as a contractarian is not because he is proponent of spontaneous order, but because he is a virtue-ethicist. I argue that Hume adopted and elaborated on the natural law account of the origins of property as conventional, but provided a different and separate account of the obligation to respect property rights.

  11. Evaluation of Glass Density to Support the Estimation of Fissile Mass Loadings from Iron Concentrations in SB6 Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, T.; Peeler, D.

    2010-12-15

    The Department of Energy - Savannah River (DOE-SR) previously provided direction to Savannah River Remediation (SRR) to maintain fissile concentration in glass below 897 g/m{sup 3}. In support of the guidance, the Savannah River National Laboratory (SRNL) provided a technical basis and a supporting Microsoft{reg_sign} Excel{reg_sign} spreadsheet for the evaluation of fissile loading in Sludge Batch 5 glass based on the Fe concentration in glass as determined by the measurements from the Slurry Mix Evaporator (SME) acceptability analysis. SRR has since requested that SRNL provide the necessary information to allow SRR to update the Excel spreadsheet so that it may be used to maintain fissile concentration in glass below 897 g/m{sup 3} during the processing of Sludge Batch 6 (SB6). One of the primary inputs into the fissile loading spreadsheet includes a bounding density for SB6-based glasses. Based on the measured density data of select SB6 variability study glasses, SRNL recommends that SRR utilize the 99/99 Upper Tolerance Limit (UTL) density value at 38% WL (2.823 g/cm{sup 3}) as a bounding density for SB6 glasses to assess the fissile concentration in this glass system. That is, the 2.823 g/cm{sup 3} is recommended as a key (and fixed) input into the fissile concentration spreadsheet for SB6 processing. It should be noted that no changes are needed to the underlying structure of the Excel based spreadsheet to support fissile assessments for SB6. However, SRR should update the other key inputs to the spreadsheet that are based on fissile and Fe concentrations reported from the SB6 Waste Acceptance Product Specification (WAPS) sample. The purpose of this technical report is to present the density measurements that were determined for the SB6 variability study glasses and to conduct a statistical evaluation of these measurements to provide a bounding density value that may be used as input to the Excel{reg_sign} spreadsheet to be employed by SRR to maintain the

  12. Spontaneous deregulation

    NARCIS (Netherlands)

    Edelman, Benjamin; Geradin, Damien

    2016-01-01

    Platform businesses such as Airbnb and Uber have risen to success partly by sidestepping laws and regulations that encumber their traditional competitors. Such rule flouting is what the authors call “spontaneous private deregulation,” and it’s happening in a growing number of industries. The authors

  13. Spontaneous deregulation

    NARCIS (Netherlands)

    Edelman, Benjamin; Geradin, Damien

    2016-01-01

    Platform businesses such as Airbnb and Uber have risen to success partly by sidestepping laws and regulations that encumber their traditional competitors. Such rule flouting is what the authors call “spontaneous private deregulation,” and it’s happening in a growing number of industries. The authors

  14. Spontaneous deregulation

    NARCIS (Netherlands)

    Edelman, Benjamin; Geradin, Damien

    Platform businesses such as Airbnb and Uber have risen to success partly by sidestepping laws and regulations that encumber their traditional competitors. Such rule flouting is what the authors call “spontaneous private deregulation,” and it’s happening in a growing number of industries. The authors

  15. Spontaneous Recovery

    Science.gov (United States)

    Rescorla, Robert A.

    2004-01-01

    Spontaneous recovery from extinction is one of the most basic phenomena of Pavlovian conditioning. Although it can be studied by using a variety of designs, some procedures are better than others for identifying the involvement of underlying learning processes. A wide range of different learning mechanisms has been suggested as being engaged by…

  16. Comparative analysis of non-destructive methods to control fissile materials in large-size containers

    Directory of Open Access Journals (Sweden)

    Batyaev V.F.

    2017-01-01

    Full Text Available The analysis of various non-destructive methods to control fissile materials (FM in large-size containers filled with radioactive waste (RAW has been carried out. The difficulty of applying passive gamma-neutron monitoring FM in large containers filled with concreted RAW is shown. Selection of an active non-destructive assay technique depends on the container contents; and in case of a concrete or iron matrix with very low activity and low activity RAW the neutron radiation method appears to be more preferable as compared with the photonuclear one.

  17. Identification of hidden fissile materials using high-pressure xenon gamma-ray detectors

    Science.gov (United States)

    Ulin, Sergey E.; Dmitrenko, Valery V.; Grachev, V. M.; Sokolov, D. V.; Uteshev, Z. M.; Chernysheva, I. V.; Vlasik, K. F.

    2001-12-01

    The description of the High Pressure Xenon Gamma-Ray Detector (HPXeD) and its main characteristics are considered in the context of the search for hidden fissile materials. The results of HPXeD measurements of gamma-radiation from radioactive sources, which are covered by lead, iron and aluminium shields, are analyzed and discussed. The use of special software for processing data is shown to improve the potential of radioactive material detection, including the identification and estimation of the main protective shield parameters.

  18. Development of a new simulation code for evaluation of criticality transients involving fissile solution boiling

    Energy Technology Data Exchange (ETDEWEB)

    Basoglu, Benan; Yamamoto, Toshihiro; Okuno, Hiroshi; Nomura, Yasushi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    In this work, we report on the development of a new computer code named TRACE for predicting the excursion characteristics of criticality excursions involving fissile solutions. TRACE employs point neutronics coupled with simple thermal-hydraulics. The temperature, the radiolytic gas effects, and the boiling phenomena are estimated using the transient heat conduction equation, a lumped-parameter energy model, and a simple boiling model, respectively. To evaluate the model, we compared our results with the results of CRAC experiments. The agreement in these comparisons is quite satisfactory. (author)

  19. Development of a new simulation code for evaluation of criticality transients involving fissile solution boiling

    Energy Technology Data Exchange (ETDEWEB)

    Basoglu, Benan; Yamamoto, Toshihiro; Okuno, Hiroshi; Nomura, Yasushi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    In this work, we report on the development of a new computer code named TRACE for predicting the excursion characteristics of criticality excursions involving fissile solutions. TRACE employs point neutronics coupled with simple thermal-hydraulics. The temperature, the radiolytic gas effects, and the boiling phenomena are estimated using the transient heat conduction equation, a lumped-parameter energy model, and a simple boiling model, respectively. To evaluate the model, we compared our results with the results of CRAC experiments. The agreement in these comparisons is quite satisfactory. (author)

  20. Nuclear dissipation effects on fission and evaporation in systems of intermediate fissility

    Directory of Open Access Journals (Sweden)

    Gelli N.

    2010-03-01

    Full Text Available The systems of intermediate fissility 132Ce and 158Er have been studied experimentally and theoretically in order to investigate the dissipation properties of nuclear matter. Cross sections of fusion-fission and evaporation residues channels together with charged particles multiplicities in both channels, their spectra, angular correlations and mass-energy distribution of fission fragments have been measured. Theoretical analysis has been performed using multi-dimensional stochastic approach with realistic treatment of particle evaporation. The results of analysis show that full one-body or unusually strong two-body dissipation allows to reproduce experimental data. No temperature dependent dissipation was needed.

  1. A single-shot nanosecond neutron pulsed technique for the detection of fissile materials

    Science.gov (United States)

    Gribkov, V.; Miklaszewski, R. A.; Chernyshova, M.; Scholz, M.; Prokopovicz, R.; Tomaszewski, K.; Drozdowicz, K.; Wiacek, U.; Gabanska, B.; Dworak, D.; Pytel, K.; Zawadka, A.

    2012-07-01

    A novel technique with the potential of detecting hidden fissile materials is presented utilizing the interaction of a single powerful and nanosecond wide neutron pulse with matter. The experimental system is based on a Dense Plasma Focus (DPF) device as a neutron source generating pulses of almost mono-energetic 2.45 MeV and/or 14.0 MeV neutrons, a few nanoseconds in width. Fissile materials, consisting of heavy nuclei, are detected utilizing two signatures: firstly by measuring those secondary fission neutrons which are faster than the elastically scattered 2.45 MeV neutrons of the D-D reaction in the DPF; secondly by measuring the pulses of the slower secondary fission neutrons following the pulse of the fast 14 MeV neutrons from the D-T reaction. In both cases it is important to compare the measured spectrum of the fission neutrons induced by the 2.45 MeV or 14 MeV neutron pulse of the DPF with theoretical spectra obtained by mathematical simulation. Therefore, results of numerical modelling of the proposed system, using the MCNP5 and the FLUKA codes are presented and compared with experimental data.

  2. Monte Carlo Modeling of Minor Actinide Burning in Fissile Spallation Targets

    Science.gov (United States)

    Malyshkin, Yury; Pshenichnov, Igor; Mishustin, Igor; Greiner, Walter

    2014-06-01

    Minor actinides (MA) present a harmful part of spent nuclear fuel due to their long half-lives and high radio-toxicity. Neutrons produced in spallation targets of Accelerator Driven Systems (ADS) can be used to transmute and burn MA. Non-fissile targets are commonly considered in ADS design. However, additional neutrons from fission reactions can be used in targets made of fissile materials. We developed a Geant4-based code MCADS (Monte Carlo model for Accelerator Driven Systems) for simulating neutron production and transport in different spallation targets. MCADS is suitable for calculating spatial distributions of neutron flux and energy deposition, neutron multiplication factors and other characteristics of produced neutrons and residual nuclei. Several modifications of the Geant4 source code described in this work were made in order to simulate targets containing MA. Results of MCADS simulations are reported for several cylindrical targets made of U+Am, Am or Am2O3 including more complicated design options with a neutron booster and a reflector. Estimations of Am burning rates are given for the considered cases.

  3. Ultraslow Wave Nuclear Burning of Uranium-Plutonium Fissile Medium on Epithermal Neutrons

    CERN Document Server

    Rusov, V D; Eingorn, M V; Chernezhenko, S A; Kakaev, A A

    2014-01-01

    For a fissile medium, originally consisting of uranium-238, the investigation of fulfillment of the wave burning criterion in a wide range of neutron energies is conducted for the first time, and a possibility of wave nuclear burning not only in the region of fast neutrons, but also for cold, epithermal and resonance ones is discovered for the first time. For the first time the results of the investigation of the Feoktistov criterion fulfillment for a fissile medium, originally consisting of uranium-238 dioxide with enrichments 4.38%, 2.00%, 1.00%, 0.71% and 0.50% with respect to uranium-235, in the region of neutron energies 0.015-10.0eV are presented. These results indicate a possibility of ultraslow wave neutron-nuclear burning mode realization in the uranium-plutonium media, originally (before the wave initiation by external neutron source) having enrichments with respect to uranium-235, corresponding to the subcritical state, in the regions of cold, thermal, epithermal and resonance neutrons. In order to...

  4. Proceedings from the Fissile Material Cut-off seminar in Stockholm

    Energy Technology Data Exchange (ETDEWEB)

    Arbman, G. [ed.

    1998-07-01

    The Swedish Defence Research Establishment hosted an international expert seminar on the subject of verifying a prohibition of the production of fissile material for nuclear weapons purpose (cut-off) in Stockholm, June 3-5 1998. The objective of the seminar was to provide an opportunity for informal discussions among scientific and technical experts on various technical matters relating to the verification of a future Fissile Material Cut-off Treaty (FMCT). A stated aim of the seminar was to keep issues of scope to a minimum. Invited speakers and commentators were given an opportunity to present their views as written contributions. The present seminar proceedings are essentially the result of these views. In addition, short summaries of the discussions following each session are included. Although an attempt was made to be as complete and accurate as possible in reproducing these discussions, the editors apologise if some important points or statements have been omitted. If so, the main reason is that the documentation of the discussions were based on written notes, not taped recordings. Eight longer contributions have been separately indexed.

  5. Feasibility study of fissile mass quantification by photofission delayed gamma rays in radioactive waste packages using MCNPX

    Science.gov (United States)

    Simon, Eric; Jallu, Fanny; Pérot, Bertrand; Plumeri, Stéphane

    2016-12-01

    The feasibility of fissile mass quantification in large, long-lived medium activity radioactive waste packages using photofission delayed gamma rays has been assessed with MCNPX. The detection limit achievable is lower than the expected uranium mass in these waste packages, but the important sensibility to the waste matrix density and sample localization imposes to get an accurate measurement of these parameters. An isotope discrimination method based on gamma-ray ratios has been evaluated showing that photofission delayed gamma rays can be used to measure the fissile mass as well as the total uranium mass.

  6. Spontaneous recovery from acalculia.

    Science.gov (United States)

    Basso, Anna; Caporali, Alessandra; Faglioni, Pietro

    2005-01-01

    A topic much considered in research on acalculia was its relationship with aphasia. Far less attention has been given to the natural course of acalculia. In this retrospective study, we examined the relationship between aphasia and acalculia in an unselected series of 98 left-brain-damaged patients and the spontaneous recovery from acalculia in 92 acalculic patients with follow-up. There was a significant association between aphasia and acalculia although 19 participants exhibited aphasia with no acalculia and six acalculia with no aphasia. We observed significant improvement between a first examination carried out between 1 and 5 months post-onset and a second examination carried out between 3 and 11 months later (mean: 5 months). The mechanisms of spontaneous recovery are discussed.

  7. DEVELOPMENT OF THE HS99 AIR TRANSPORT TYPE A FISSILE PACKAGE

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, P.; Eberl, K.

    2012-07-10

    An air-transport Type A Fissile radioactive shipping package for the transport of special form uranium sources has been developed by the Savannah River National Laboratory (SRNL) for the Department of Homeland Security. The Package model number is HS99 for Homeland Security Model 99. This paper presents the major design features of the HS99 and highlights engineered materials necessary for meeting the design requirements for this light-weight Type AF packaging. A discussion is provided demonstrating how the HS99 complies with the regulatory safety requirements of the Nuclear Regulatory Commission. The paper summarizes the results of structural testing to specified in 10 CFR 71 for Normal Conditions of Transport and Hypothetical Accident Conditions events. Planned and proposed future missions for this packaging are also addressed.

  8. A comparative study between transport and criticality safety indexes for fissile uranium nuclearly pure

    Energy Technology Data Exchange (ETDEWEB)

    Moraes da Silva, T. de; Sordi, G.M.A.A. [Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN (Brazil)]. e-mail: tmsilva@ipen.br

    2006-07-01

    The international and national standards determine that during the transport of radioactive materials the package to be sent should be identified by labels of risks specifying content, activity and the transport index. The result of the monitoring of the package to 1 meter identifies the transport index, TI, which represents the dose rate to 1 meter of this. The transport index is, by definition, a number that represents a gamma radiation that crosses the superficial layer the radioactive material of the package to 1 meter of distance. For the fissile radioactive material that is the one in which a neutron causes the division of the atom, the international standards specify criticality safety index CSI, which is related with the safe mass of the fissile element. In this work it was determined the respective safe mass for each considered enrichment for the compounds of uranium oxides UO{sub 2}, U{sub 3}O{sub 8} and U{sub 3}Si{sub 2}. In the study of CSI it was observed that the value 50 of the expression 50/N being N the number of packages be transported in subcriticality conditions it represents a fifth part of the safe mass of the element uranium or 9% of the smallest mass critical for a transport not under exclusive use. As conclusion of the accomplished study was observed that the transport index starting from 7% of enrichment doesn't present contribution and that criticality safety index is always greater than the transport index. Therefore what the standards demand to specify, the largest value between both indexes, was clearly identified in this study as being the criticality safety index. (Author)

  9. In-Drift Accumulation of Fissile Material From Waste Packages Containing Plutonium Disposition Waste Form

    Energy Technology Data Exchange (ETDEWEB)

    H.W> Stockman; S. LeStrange

    2000-09-28

    The objective of this calculation is to provide estimates of the amount of fissile material flowing out of the waste package (source term) and the accumulation of fissile elements (U and Pu) in a crushed-tuff invert. These calculations provide input for the analysis of repository impacts of the Pu-ceramic waste forms. In particular, the source term results are used as input to the far-field accumulation calculation reported in Ref. 51, and the in-drift accumulation results are used as inputs for the criticality calculations reported in Ref. 2. The results are also summarized and interpreted in Ref. 52. The scope of this calculation is the waste package (WP) Viability Assessment (VA) design, which consists of an outer corrosion-allowance material (CAM) and an inner corrosion-resistant material (CRM). This design is used in this calculation in order to be consistent with earlier Pu-ceramic degradation calculations (Ref. 15). The impact of the new Enhanced Design Alternative-I1 (EDA-11) design on the results will be addressed in a subsequent report. The design of the invert (a leveling foundation, which creates a level surface of the drift floor and supports the WP mounting structure) is consistent with the EDA-I1 design. The invert will be composed of crushed stone and a steel support structure (Ref. 17). The scope of this calculation is also defined by the nominal degradation scenario, which involves the breach of the WP (Section 10.5.1.2, Ref. 48), followed by the influx of water. Water in the WP may, in time, gradually leach the fissile components and neutron absorbers out of the ceramic waste forms. Thus, the water in the WP may become laden with dissolved actinides (e.g., Pu and U), and may eventually overflow or leak from the WP. Once the water leaves the WP, it may encounter the invert, in which the actinides may reprecipitate. Several factors could induce reprecipitation; these factors include: the high surface area of the crushed stone, and the presence of

  10. A new class of spontaneously polarized materials

    DEFF Research Database (Denmark)

    Field, David; Plekan, Oksana; Cassidy, Andrew;

    2011-01-01

    Very large electric fields form spontaneously within films of seemingly prosaic chemicals such as nitrous oxide or propane.We describe how the discovery of this unexpected phenomenon took place and how we attempt to understand the nature of the new class of spontaneously polarized materials, rese...

  11. Measurement of fissile mass in large-size containers with a transportable linear accelerator

    Science.gov (United States)

    Romeyer Dherbey, Jacques; Lyoussi, A.; Buisson, A.

    1997-02-01

    The quantification of transuranic material (TRU) in waste packages is a common problem of countries working in the field of nuclear nondestructive inspection. The direct measurement of TRU mass inside large size closed containers is difficult due to several effects, mainly the matrix attenuation and uncertainty on the localization of the radioactive mass. The present document describes the method being developed to assay conditioned waste packages using a transportable linear accelerator which is called Mini- Linatron. The system uses a pulsed electron beam from the Mini-Linatron to produce high energy bremsstrahlung photon bursts from thin metallic converter. The transportable linear accelerator operates at 6, 9 and 11 MeV with a repetition rate between 10 to 300 Hz and a 4.5 microsecond(s) pulse duration. The maximum gamma dose rate is about 23 Gy/mn at 1 m. The photons induce fission in fissile and fertile nuclei. We counted delayed neutrons emitted after each pulse by using Sequential Photon Interrogation and Neutron Counting Signatures technique which has ben developed in this framework. Results of measurements on an experimental active gamma interrogation facility for embedded intermediate and low level wastes are presented. Finally, the advantages and performances of the photofission interrogation technique, the use of a transportable electron linear accelerator as a particle source, and the experimental and electronic details will be discussed.

  12. The use of a transportable linear accelerator for fissile mass measurements

    Science.gov (United States)

    Romeyer Dherbey, J.; Lyoussi, A.; Buisson, A.

    1997-02-01

    The quantification of transuranic material (TRU) in waste packages is a common care of countries working in the field of nuclear nondestructive prospecting. The direct control of TRU mass inside large size closed containers is difficult due to several effects, mainly the matrix attenuation and uncertainty on the localization of the radioactive mass. The present document describes the method being developed to assay conditioned waste packages using a transportable linear accelerator which is called Mini-Linatron. The system uses a pulsed electron beam from the Mini-Linatron to produce high energy bremsstrahlung photon bursts from thin metallic converter. The transportable linear accelerator operates at 6, 9 and 11 MeV with a repetition rate between 10 to 300 Hz and a 4.5 μs pulse duration. The maximum gamma dose rate is about 23 Gy/mn at 1 m. The photons induce fission in fissile and fertile nuclei. We counted delayed neutrons emitted after each pulse. Results of measurements on an experimental active gamma interrogation facility for embedded intermediate and low level wastes are presented.

  13. Analysis of triso packing fraction and fissile material to DB-MHR using LWR reprocessed fuel

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Clarysson A.M. da; Pereira, Claubia; Costa, Antonella L.; Veloso, Maria Auxiliadora F.; Gual, Maritza R., E-mail: clarysson@nuclear.ufmg.br, E-mail: claubia@nuclear.ufmg.br, E-mail: antonella@nuclear.ufmg.br, E-mail: dora@nuclear.ufmg.br, E-mail: maritzargual@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear

    2013-07-01

    Gas-cooled and graphite-moderated reactor is being considered the next generation of nuclear power plants because of its characteristic to operate with reprocessed fuel. The typical fuel element consists of a hexagonal block with coolant and fuel channels. The fuel pin is manufactured into compacted ceramic-coated particles (TRISO) which are used to achieve both a high burnup and a high degree of passive safety. This work uses the MCNPX 2.6.0 to simulate the active core of Deep Burn Modular Helium Reactor (DB-MHR) employing PWR (Pressurized Water Reactor) reprocessed fuel. However, before a complete study of DB-MHR fuel cycle and recharge, it is necessary to evaluate the neutronic parameters to some values of TRISO Packing Fractions (PF) and Fissile Material (FM). Each PF and FM combination would generate the best behaviour of neutronic parameters. Therefore, this study configures several PF and FM combinations considering the heterogeneity of TRISO layers and lattice. The results present the best combination of PF and FM values according with the more appropriated behaviour of the neutronic parameters during the burnup. In this way, the optimized combination can be used to future works of MHR fuel cycle and recharge. (author)

  14. Spontaneous baryogenesis from asymmetric inflaton

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Yamada, Masaki [Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Tokyo Univ., Chiba (Japan). Inst. for Cosmic Ray Research; DESY Hamburg (Germany)

    2015-10-15

    We propose a variant scenario of spontaneous baryogenesis from asymmetric inflaton based on current-current interactions between the inflaton and matter fields with a non-zero B-L charge. When the inflaton starts to oscillate around the minimum after inflation, it may lead to excitation of a CP-odd component, which induces an effective chemical potential for the B-L number through the current-current interactions. We study concrete inflation models and show that the spontaneous baryogenesis scenario can be naturally implemented in the chaotic inflation in supergravity.

  15. Autoreactive IgE in Chronic Spontaneous/Idiopathic Urticaria and Basophil/Mastocyte Priming Phenomenon, as a Feature of Autoimmune Nature of the Syndrome.

    Science.gov (United States)

    Panaszek, Bernard; Pawłowicz, Robert; Grzegrzółka, Jędrzej; Obojski, Andrzej

    2017-04-01

    Recent years of research have shed a new light on the role of IgE in immune reactions. It seems to be more than just a contribution to immediate type of allergic response. It appears that monomeric IgE may enhance mast cell activity without cross-linking of FcεRI by IgE specific allergen or autoreactive IgG anti-IgE antibodies. Monomeric IgE molecules are heterogeneous concerning their ability to induce survival and activation of mast cells only by binding the IgE to FcεRI, but not affecting degranulation of cells. It also turned out that IgE may react to autoantigens occurring in the blood not only in chronic spontaneous urticaria (CSU) but also in other autoimmune diseases. The aforementioned phenomena may promote the activity of mast cells/basophils in CSU that easily degranulate when influenced by various inner (autoreactive IgG against IgE and FcεRI, autoreactive IgE for self-antigens) and outer factors (cold, heat, pressure) or allergens. These findings forced the new approach to the role of autoimmunity, self-antigens and IgE autoantibodies in the pathology of CSU. CSU put in the scheme of autoreactive IgG and autoreactive IgE seems to be either a kind of an autoimmune disease or a clinical manifestation of some other defined autoimmune diseases or both.

  16. Far-Field Accumulation of Fissile Material From Waste Packages Containing Plutonium Disposition Waste Form

    Energy Technology Data Exchange (ETDEWEB)

    J.P. Nicot

    2000-09-29

    The objective of this calculation is to estimate the quantity of fissile material that could accumulate in fractures in the rock beneath plutonium-ceramic (Pu-ceramic) and Mixed-Oxide (MOX) waste packages (WPs) as they degrade in the potential monitored geologic repository at Yucca Mountain. This calculation is to feed another calculation (Ref. 31) computing the probability of criticality in the systems described in Section 6 and then ultimately to a more general report on the impact of plutonium on the performance of the proposed repository (Ref. 32), both developed concurrently to this work. This calculation is done in accordance with the development plan TDP-DDC-MD-000001 (Ref. 9), item 5. The original document described in item 5 has been split into two documents: this calculation and Ref. 4. The scope of the calculation is limited to only very low flow rates because they lead to the most conservative cases for Pu accumulation and more generally are consistent with the way the effluent from the WP (called source term in this calculation) was calculated (Ref. 4). Ref. 4 (''In-Drift Accumulation of Fissile Material from WPs Containing Plutonium Disposition Waste Forms'') details the evolution through time (breach time is initial time) of the chemical composition of the solution inside the WP as degradation of the fuel and other materials proceed. It is the chemical solution used as a source term in this calculation. Ref. 4 takes that same source term and reacts it with the invert; this calculation reacts it with the rock. In addition to reactions with the rock minerals (that release Si and Ca), the basic mechanisms for actinide precipitation are dilution and mixing with resident water as explained in Section 2.1.4. No other potential mechanism such as flow through a reducing zone is investigated in this calculation. No attempt was made to use the effluent water from the bottom of the invert instead of using directly the effluent water from the

  17. Open literature review of threats including sabotage and theft of fissile material transport in Japan.

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, John Russell; Furaus, James Phillip; Marincel, Michelle K.

    2005-06-01

    This report is a review of open literature concerning threats including sabotage and theft related to fissile material transport in Japan. It is intended to aid Japanese officials in the development of a design basis threat. This threat includes the external threats of the terrorist, criminal, and extremist, and the insider threats of the disgruntled employee, the employee forced into cooperation via coercion, the psychotic employee, and the criminal employee. Examination of the external terrorist threat considers Japanese demographics, known terrorist groups in Japan, and the international relations of Japan. Demographically, Japan has a relatively homogenous population, both ethnically and religiously. Japan is a relatively peaceful nation, but its history illustrates that it is not immune to terrorism. It has a history of domestic terrorism and the open literature points to the Red Army, Aum Shinrikyo, Chukaku-Ha, and Seikijuku. Japan supports the United States in its war on terrorism and in Iraq, which may make Japan a target for both international and domestic terrorists. Crime appears to remain low in Japan; however sources note that the foreign crime rate is increasing as the number of foreign nationals in the country increases. Antinuclear groups' recent foci have been nuclear reprocessing technology, transportation of MOX fuel, and possible related nuclear proliferation issues. The insider threat is first defined by the threat of the disgruntled employee. This threat can be determined by studying the history of Japan's employment system, where Keiretsu have provided company stability and lifetime employment. Recent economic difficulties and an increase of corporate crime, due to sole reliability on the honor code, have begun to erode employee loyalty.

  18. High-power, photofission-inducing bremsstrahlung source for intense pulsed active detection of fissile material

    Directory of Open Access Journals (Sweden)

    J. C. Zier

    2014-06-01

    Full Text Available Intense pulsed active detection (IPAD is a promising technique for detecting fissile material to prevent the proliferation of special nuclear materials. With IPAD, fissions are induced in a brief, intense radiation burst and the resulting gamma ray or neutron signals are acquired during a short period of elevated signal-to-noise ratio. The 8 MV, 200 kA Mercury pulsed-power generator at the Naval Research Laboratory coupled to a high-power vacuum diode produces an intense 30 ns bremsstrahlung beam to study this approach. The work presented here reports on Mercury experiments designed to maximize the photofission yield in a depleted-uranium (DU object in the bremsstrahlung far field by varying the anode-cathode (AK diode gap spacing and by adding an inner-diameter-reducing insert in the outer conductor wall. An extensive suite of diagnostics was fielded to measure the bremsstrahlung beam and DU fission yield as functions of diode geometry. Delayed fission neutrons from the DU proved to be a valuable diagnostic for measuring bremsstrahlung photons above 5 MeV. The measurements are in broad agreement with particle-in-cell and Monte Carlo simulations of electron dynamics and radiation transport. These show that with increasing AK gap, electron losses to the insert and outer conductor wall increase and that the electron angles impacting the bremsstrahlung converter approach normal incidence. The diode conditions for maximum fission yield occur when the gap is large enough to produce electron angles close to normal, yet small enough to limit electron losses.

  19. Effect of transverse vibrations of fissile nuclei on the angular and spin distributions of low-energy fission fragments

    Science.gov (United States)

    Bunakov, V. E.; Kadmensky, S. G.; Lyubashevsky, D. E.

    2016-05-01

    It is shown that A. Bohr's classic theory of angular distributions of fragments originating from low-energy fission should be supplemented with quantum corrections based on the involvement of a superposition of a very large number of angular momenta L m in the description of the relative motion of fragments flying apart along the straight line coincidentwith the symmetry axis. It is revealed that quantum zero-point wriggling-type vibrations of the fissile system in the vicinity of its scission point are a source of these angular momenta and of high fragment spins observed experimentally.

  20. Technical evaluation panel summary report. Ceramic and glass immobilization options fissile materials disposition program

    Energy Technology Data Exchange (ETDEWEB)

    Myers, B. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brummond, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Armantrout, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shaw, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jantzen, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jostons, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McKibben, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Strachan, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vienna, J. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    1997-12-23

    This report documents the results of a technical evaluation of the merits of ceramic and glass immobilization forms for the disposition of surplus weapons-useable plutonium. The evaluation was conducted by a Technical Evaluation Panel (TEP), whose members were selected to cover a relevant range of scientific and technical expertise and represented each of the technical organizations involved in the Plutonium Immobilization Program. The TEP held a formal review at Lawrence Liver-more National Laboratory (LLNL) from July 2%August 1, 1997. Following this review, the TEP documented the review and its evaluation of the two immobilization technologies in this report to provide a technical basis for a recommendation by LLNL to the Department of Energy (DOE) for the preferred immobilization form. The comparison of the glass and ceramic forms and manufacturing processes was a tremendous challenge to the TEP. The two forms and their processes are similar in many ways. The TEP went to great effort to accurately assess what were, in many cases, fine details of the processes, unit operations, and the glass and ceramic forms themselves. The set of criteria used by the Fissile Materials Disposition Program (FMDP) in past screenings and down-selections was used to measure-the two options. One exception is that the TEP did not consider criteria that were largely nontechnical (namely international impact, public acceptance, and effects on other : DOE programs). The TEP' s measures and assessments are documented in detail. Care was taken to ensure that the data used were well documented and traceable to their source. Although no final conclusion regarding the preferred form was reached or explicitly stated in this report (this was not within the TEP' s charter), no "show stoppers" were identified for either form. Both forms appear capable of satisfying all the criteria, as interpreted by the TEP. The TEP identified a number of distinct and quantifiable differences between

  1. Tank 40 final sludge batch 9 chemical and fissile radionuclide characterization results

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kubilius, W. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Pareizs, J. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-06-26

    A sample of Sludge Batch (SB) 9 was pulled from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS)i. The SB9 WAPS sample was also analyzed for chemical composition, including noble metals, and fissile constituents, and these results are reported here. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is fed to the Defense Waste Processing Facility (DWPF) as SB9. At the Savannah River National Laboratory (SRNL), the 3-L Tank 40 SB9 sample was transferred from the shipping container into a 4-L high density polyethylene bottle and solids were allowed to settle. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 547 g sub-sample was removed. This sub-sample was then utilized for all subsequent slurry sample preparations. Eight separate aliquots of the slurry were digested, four with HNO3/HCl (aqua regiaii) in sealed Teflon® vessels and four with NaOH/Na2O2 (alkali or peroxide fusioniii) using Zr crucibles. Three Analytical Reference Glass – 1iv (ARG-1) standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted to 1:100 with deionized water and submitted to Analytical Development (AD) for inductively coupled plasma – atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma – mass spectrometry (ICP-MS) analysis, atomic absorption spectroscopy (AA) for As and Se, and cold vapor atomic absorption spectroscopy (CV-AA) for Hg. Equivalent dilutions of the alkali fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB9 supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES, ion chromatography (IC), total base/free OH-/other base, total inorganic

  2. Analyse of the potential of the high temperature reactor with respect to the use of fissile materials; Analyse des capacites des reacteurs a haute temperature sous l'aspect de l'utilisation des matieres fissiles

    Energy Technology Data Exchange (ETDEWEB)

    Damian, F

    2001-07-01

    The high temperature reactors fuel is made of micro-particles dispersed in a graphite matrix. This configuration makes it possible to reach high burnup, higher than 700 GWj/t. Thanks to the decoupling between the thermal and the neutronic behaviors in the core many types of fuels can be used. These characteristics give to HTR reactor very good capacities to burn fissile materials. This work was done in the frame of the evaluation of HTR capacities to enhance the value of the plutonium stocks. These stocks are currently composed of the irradiated fuels discharged from classical PWR or the dismantling of the nuclear weapons and represent a significant energy potential. These studies concluded that high cycles length can be reached whatever the plutonium quality is (from 50 % to 94 % of fissile plutonium). In addition, it was demonstrated that the moderator temperature coefficient becomes locally positive for highly burn fuel while the core global moderator temperature coefficient remained negative in the operation range of the reactor. A significant share of this work was first devoted to the setting of a modeling of the fuel element but also of the reactor's core with the codes of system SAPHYR. The whole of modeling was validated by reference calculations. This work of code assessment is justified by a preliminary work that showed that the classical calculation scheme used for PWR could not be transposed directly to HTR core. (author)

  3. Entropy Growth Is the Manifestation of Spontaneity

    Directory of Open Access Journals (Sweden)

    Lin-Shu Wang

    2014-01-01

    Full Text Available Every student of thermodynamics grasps entropy growth in terms of dissipation of energy. The real nature of energy and entropy is subtle. This critical review of the evolution of thermodynamic thought uncovers the remarkable advance on our understanding of energy made by Kelvin with his dissipation of energy proposition. Maxwell and Planck, however, pointed out that dissipation of energy does not exhaust growth of entropy (i.e., the idea of spontaneity, and in fact, as it is shown here, Kelvin’s proposition of dissipation of energy (1852 is subsumed under the principle of the increase of entropy (Clausius, 1865. It is necessary, therefore, for thermodynamics to become a coherent conceptual system, to introduce spontaneity as an independent concept. Instead of the heat-work dyad framework, the introduction of spontaneity entails energy transformation to be viewed in terms of a triad framework of heat (from the reservoir-work-spontaneity. Spontaneity is the new energy in the triad framework, and it is also clear that energy commodity (fungible energy or energy carriers is only one kind of spontaneity, stock spontaneity; the other kind is ongoing spontaneity, the consideration of which is necessary for comprehending problems of homeostasis in both the organic and inorganic worlds.

  4. Repackaging of High Fissile TRU Waste at the Transuranic Waste Processing Center - 13240

    Energy Technology Data Exchange (ETDEWEB)

    Oakley, Brian; Heacker, Fred [WAI, TRU Waste Processing Center, 100 WIPP Road Lenoir City, TN 37771 (United States); McMillan, Bill [DOE, Oak Ridge Operations, Bldg. 2714, Oak Ridge, TN 37830 (United States)

    2013-07-01

    Twenty-six drums of high fissile transuranic (TRU) waste from Oak Ridge National Laboratory (ORNL) operations were declared waste in the mid-1980's and placed in storage with the legacy TRU waste inventory for future treatment and disposal at the Waste Isolation Pilot Plant (WIPP). Repackaging and treatment of the waste at the TRU Waste Packaging Center (TWPC) will require the installation of additional equipment and capabilities to address the hazards for handling and repackaging the waste compared to typical Contact Handled (CH) TRU waste that is processed at the TWPC, including potential hydrogen accumulation in legacy 6M/2R packaging configurations, potential presence of reactive plutonium hydrides, and significant low energy gamma radiation dose rates. All of the waste is anticipated to be repackaged at the TWPC and certified for disposal at WIPP. The waste is currently packaged in multiple layers of containers which presents additional challenges for repackaging activities due to the potential for the accumulation of hydrogen gas in the container headspace in quantities than could exceed the Lower Flammability Limit (LFL). The outer container for each waste package is a stainless steel 0.21 m{sup 3} (55-gal) drum which contains either a 0.04 m{sup 3} or 0.06 m{sup 3} (10-gal or 15-gal) 6M drum. The inner 2R container in each 6M drum is ∼12 cm (5 in) outside diameter x 30-36 cm (12-14 in) long and is considered to be a > 4 liter sealed container relative to TRU waste packaging criteria. Inside the 2R containers are multiple configurations of food pack cans, pipe nipples, and welded capsules. The waste contains significant quantities of high burn-up plutonium oxides and metals with a heavy weight percentage of higher atomic mass isotopes and the subsequent in-growth of significant quantities of americium. Significant low energy gamma radiation is expected to be present due to the americium in-growth. Radiation dose rates on inner containers are estimated

  5. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  6. Expression of Interferon γ by Decidual Cells and Natural Killer Cells at the Human Implantation Site: Implications for Preeclampsia, Spontaneous Abortion, and Intrauterine Growth Restriction.

    Science.gov (United States)

    Chen, Chie-Pein; Piao, Longzhu; Chen, Xilin; Yu, Jianhua; Masch, Rachel; Schatz, Frederick; Lockwood, Charles J; Huang, S Joseph

    2015-11-01

    Human first-trimester decidual cells (FTDCs) chemoattract CXCR3-expressing circulating CD56(bright)CD16(-) natural killer (NK) cells, which increase uteroplacental blood flow by remodeling spiral arteries and arterioles. This recruitment reflects elevated FTDC expression of NK cell-recruiting induced protein 10 and interferon (IFN)-inducible T-cell-α chemoattractant produced in response to the synergistic effects of tumor necrosis factor α (TNF-α) and IFN-γ stimulation. Decidual macrophages express TNF-α, whereas the cellular origin of IFN-γ is unclear. Therefore, this study aims to identify the cell source(s) of IFN-γ in human first trimester decidua. Immunostaining of decidual sections revealed that both FTDCs and decidual NK (dNK) cells express IFN-γ. Although individual dNK cells express higher IFN-γ levels, the more numerous FTDCs account for greater proportion of total IFN-γ immunostaining. Freshly isolated FTDCs express greater IFN-γ staining than dNK cells as measured by flow cytometry, whereas incubation of dNK cells with documented NK cell activators significantly increases IFN-γ above FTDC levels. Confluent FTDCs intrinsically produce, but paradoxically respond to, exogenous IFN-γ.

  7. Spontaneous external gallbladder perforation

    Energy Technology Data Exchange (ETDEWEB)

    Noeldge, G.; Wimmer, B.; Kirchner, R.

    1981-04-01

    Spontaneous perforation of the gallbladder is one complication of cholelithiasis. There is a greater occurence of free perforation in the peritoneal cavity with bilary pertonitis, followed by the perforation into the stomach, small intestine and colon. A single case of the nowadays rare spontaneous perforation in and through the abdominal wall will be reported. Spontaneous gallbladder perforation appears nearly asymptomatic in its clinical course because of absent biliary peritonitis.

  8. Fissility of actinide nuclei induced by 60-130 MeV photons; Fissionabilidade de nucleos actnideos induzida por fotons de energia 60-130 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Morcelle, Viviane; Tavares, Odilon A.P

    2004-06-15

    Nuclear fissilities obtained from recent photofission reaction cross section measurements carried out at Saskatchewan Accelerator Laboratory (Saskatoon, Canada) in the energy range 60-130 MeV for {sup 232} Th, {sup 233} U, {sup 235} U, {sup 238} U, and {sup 237} Np nuclei have been analysed in a systematic way. To this aim, a semiempirical approach has been developed based on the quasi-deuteron nuclear photoabsorption model followed by the process of competition between neutron evaporation and fission for the excited nucleus. The study reproduces satisfactorily well the increasing trend of nuclear fissility with parameter Z{sup 2}=A. (author)

  9. Peritonitis - spontaneous bacterial

    Science.gov (United States)

    Spontaneous bacterial peritonitis (SBP); Ascites - peritonitis; Cirrhosis - peritonitis ... who are on peritoneal dialysis for kidney failure. Peritonitis may have other causes . These include infection from ...

  10. Mineralogy and microstructure of roofing slate: thermo-optical behaviour and fissility

    Directory of Open Access Journals (Sweden)

    García-Guinea, J.

    1998-09-01

    Full Text Available The mineralogy and microstructure, which affect the slaty cleavage, are linked with the strong preferred orientation of phyllosilicates and this enables the rock to be split into large, thin, flat sheets. Roofing slate samples with different commercial fissilities have been analyzed by radioluminescence (RL, thermoluminescence (3DTL, by X-ray diffraction (XRD, by scanning electron microscopy (SEM using the back-scattered mode (BSEI and by electron microprobe (EMP. They are made up of white micas, chlorite, quartz, detrital feldspars, ilmenite, pyrite, rutile apatite and tourmaline. Texturally, all consist of silt-sized clasts of detrital quartz, feldspars, chlorite-mica stacks, muscovite and ilmenite in a recrystalline, lepidoblastic matrix of white micas and chlorite with quartz lenses, all showing a very strong preferred orientation. The luminescence emission centers are a low broad blue band around the 400 nm spectra positions linked with alkali losses and formation of [AlO4]º defects; a peak at 473 nm interpreted as a the first thermal step (150-300ºC of a non-isothermal dehydroxylation of the slate phyllosilicates; and a 568 nm peak which agrees with Mn2+ point defects in aluminosilicate lattices. The studies on the slaty cleavage could be significant because Spain is the largest producer of roofing slate tiles in the world (87% of world production.

    La exfoliación de las pizarras depende fundamentalmente de su mineralogía y microestructura, especialmente de la fuerte orientación de los filosilicatos. Esta propiedad permite hendir o abrir las pizarras de techar en láminas muy grandes, delgadas y planas. Se han analizado varias pizarras de techar con diferentes calidades comerciales, correspondientes a diferentes grados de físibilidad, por radioluminiscencia (RL, termoluminiscencia espectral (TL3D, difracción de rayos X (DRX, microscopía electrónica de barrido (MEB utilizando el modo backscattered (BSEI

  11. Spontaneous intracranial hypotension.

    LENUS (Irish Health Repository)

    Fullam, L

    2012-01-31

    INTRODUCTION: Spontaneous\\/primary intracranial hypotension is characterised by orthostatic headache and is associated with characteristic magnetic resonance imaging findings. CASE REPORT: We present a case report of a patient with typical symptoms and classical radiological images. DISCUSSION: Spontaneous intracranial hypotension is an under-recognised cause of headache and can be diagnosed by history of typical orthostatic headache and findings on MRI brain.

  12. Nonproliferation and arms control assessment of weapons-usable fissile material storage and excess plutonium disposition alternatives

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    This report has been prepared by the Department of Energy`s Office of Arms Control and Nonproliferation (DOE-NN) with support from the Office of Fissile Materials Disposition (DOE-MD). Its purpose is to analyze the nonproliferation and arms reduction implications of the alternatives for storage of plutonium and HEU, and disposition of excess plutonium, to aid policymakers and the public in making final decisions. While this assessment describes the benefits and risks associated with each option, it does not attempt to rank order the options or choose which ones are best. It does, however, identify steps which could maximize the benefits and mitigate any vulnerabilities of the various alternatives under consideration.

  13. FATE OF FISSILE MATERIAL BOUND TO MONOSODIUM TITANATE DURING COOPER CATALYZED PEROXIDE OXIDATION OF TANK 48H WASTE

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K.

    2012-08-09

    At the Savannah River Site (SRS), Tank 48H currently holds approximately 240,000 gallons of slurry which contains potassium and cesium tetraphenylborate (TPB). A copper catalyzed peroxide oxidation (CCPO) reaction is currently being examined as a method for destroying the TPB present in Tank 48H. Part of the development of that process includes an examination of the fate of the Tank 48H fissile material which is adsorbed onto monosodium titanate (MST) particles. This report details results from experiments designed to examine the potential degradation of MST during CCPO processing and the subsequent fate of the adsorbed fissile material. Experiments were conducted to simulate the CCPO process on MST solids loaded with sorbates in a simplified Tank 48H simulant. Loaded MST solids were placed into the Tank 48H simplified simulant without TPB, and the experiments were then carried through acid addition (pH adjustment to 11), peroxide addition, holding at temperature (50 C) for one week, and finally NaOH addition to bring the free hydroxide concentration to a target concentration of 1 M. Testing was conducted without TPB to show the maximum possible impact on MST since the competing oxidation of TPB with peroxide was absent. In addition, the Cu catalyst was also omitted, which will maximize the interaction of H{sub 2}O{sub 2} with the MST; however, the results may be non-conservative assuming the Cu-peroxide active intermediate is more reactive than the peroxide radical itself. The study found that both U and Pu desorb from the MST when the peroxide addition begins, although to different extents. Virtually all of the U goes into solution at the beginning of the peroxide addition, whereas Pu reaches a maximum of {approx}34% leached during the peroxide addition. Ti from the MST was also found to come into solution during the peroxide addition. Therefore, Ti is present with the fissile in solution. After the peroxide addition is complete, the Pu and Ti are found to

  14. The nature of spontaneous sleep across adulthood

    National Research Council Canada - National Science Library

    CAMPBELL, SCOTT S; MURPHY, PATRICIA J

    2007-01-01

    ...’ protocol, we studied such sleep in young, middle‐aged and older adults. All subjects exhibited polyphasic sleep patterns, characterized by relatively short intervals of both sleep and waking...

  15. Spontaneous rupture of pyometra

    National Research Council Canada - National Science Library

    Mallah, Fatemeh; Eftekhar, Tahere; Naghavi-Behzad, Mohammad

    2013-01-01

    Spontaneous perforation is a very rare complication of pyometra. The clinical findings of perforated pyometra are similar to perforation of the gastrointestinal tract and other causes of acute abdomen...

  16. Spontaneous Rupture of Pyometra

    OpenAIRE

    Fatemeh Mallah; Tahere Eftekhar; Mohammad Naghavi-Behzad

    2013-01-01

    Spontaneous perforation is a very rare complication of pyometra. The clinical findings of perforated pyometra are similar to perforation of the gastrointestinal tract and other causes of acute abdomen. In most cases, a correct and definite diagnosis can be made only by laparotomy. We report two cases of diffuse peritonitis caused by spontaneous perforated pyometra. The first case is a 78-year-old woman with abdominal pain for which laparotomy was performed because of suspected incarcerated he...

  17. Geometrical hierarchy and spontaneous symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Farakos, K.; Koutsoumbas, G.; Surridge, M.; Zoupanos, G.

    1987-06-04

    A four-dimensional gauge theory, where Higgs fields and the corresponding potential appear naturally, is obtained by dimensionally reducing a pure gauge theory over a compact coset space S/R. We show, using an explicit example, that a hierarchy of the scales in the coset space can change the spontaneous symmetry breaking of the four-dimensional gauge theory.

  18. Spontaneous Activity Drives Local Synaptic Plasticity In Vivo

    NARCIS (Netherlands)

    Winnubst, Johan; Cheyne, Juliette E; Niculescu, Dragos; Lohmann, C.

    2015-01-01

    Spontaneous activity fine-tunes neuronal connections in the developing brain. To explore the underlying synaptic plasticity mechanisms, we monitored naturally occurring changes in spontaneous activity at individual synapses with whole-cell patch-clamp recordings and simultaneous calcium imaging in

  19. Case of spontaneous ventriculocisternostomy

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, Kanji; Yoshimoto, Hisanori; Harada, Kiyoshi; Uozumi, Tohru (Hiroshima Univ. (Japan). School of Medicine); Kuwabara, Satoshi

    1983-05-01

    The authors experienced a case of spontaneous ventriculocisternostomy diagnosed by CT scan with metrizamide and Conray. Patient was 23-year-old male who had been in good health until one month before admission, when he began to have headache and tinnitus. He noticed bilateral visual acuity was decreased about one week before admission and vomiting appeared two days before admission. He was admitted to our hospital because of bilateral papilledema and remarkable hydrocephalus diagnosed by CT scan. On admission, no abnormal neurological signs except for bilateral papilledema were noted. Immediately, right ventricular drainage was performed. Pressure of the ventricle was over 300mmH/sub 2/O and CSF was clear. PVG and PEG disclosed an another cavity behind the third ventricle, which was communicated with the third ventricle, and occlusion of aqueduct of Sylvius. Metrizamide CT scan and Conray CT scan showed a communication between this cavity and quadrigeminal and supracerebellar cisterns. On these neuroradiological findings, the diagnosis of obstructive hydrocephalus due to benign aqueduct stenosis accompanied with spontaneous ventriculocisternostomy was obtained. Spontaneous ventriculocisternostomy was noticed to produce arrest of hydrocephalus, but with our case, spontaneous regression of such symptoms did not appeared. By surgical ventriculocisternostomy (method by Torkildsen, Dandy, or Scarff), arrest of hydrocephalus was seen in about 50 to 70 per cent, which was the same results as those of spontaneous ventriculocisternostomy. It is concluded that VP shunt or VA shunt is thought to be better treatment of obstructive hydrocephalus than the various kinds of surgical ventriculocisternostomy.

  20. Constraints on Spontaneous Entrainment

    Directory of Open Access Journals (Sweden)

    Richardson Michael J.

    2011-12-01

    Full Text Available Past research has revealed that a person's rhythmic limb movements become spontaneously entrained to an environmental rhythm if a. visual information about the environmental rhythm is available and b. its frequency of the environmental rhythm is near that of the person's movements. Further, this research has demonstrated that if the eyes track the environmental stimulus, the spontaneous entrainment to the environmental rhythm is strengthened. Experiments were performed to investigate two hypotheses that could explain this eye-tracking enhancement of spontaneous entrainment. One hypothesis is that eye tracking allows for the pick up of important coordinative information at the turn-around points of a movement trajectory. Another hypothesis is that the limb movements entrain to the moving eyes through a neuromotor synergy linking the eyes and limb. Results of these experiments will help delineate the informational and dynamical constraints that can impact the acquisition of skilled actions.

  1. [Primary spontaneous pneumomediastinum].

    Science.gov (United States)

    Togashi, K; Hosaka, Y

    2007-12-01

    We report 5 cases of spontaneous pneumomediastinum. They were 4 men and 1 female with a mean age of 17 (14-25). Four patients developed sport-related pneumomediastinum and 1 patient had a karaoke-related condition. Primary spontaneous pneumomediasinum is a rare condition. In addition, there is no previous report describing karaoke-related spontaneous pneumomediastinum. Each of the patients experienced chest pain and/or neck pain before consulting our hospital. Chest roentgenogram and chest computed tomography showed pneumomediastinum without esophageal or tracheal injury. Four patients did not require hospitalization, but 1 patient was necessary to hospitalize for 7 days because of severe chest and neck pain. None of these 5 patients has had any recurrence for more than 1 year. Differentiating this entity from other diseases involving anterior chest pain is important.

  2. Spontaneous Perforation of Pyometra

    Directory of Open Access Journals (Sweden)

    Begüm Yildizhan

    2006-01-01

    Full Text Available Pyometra is the accumulation of purulent material in the uterine cavity. Its reported incidence is 0.01–0.5% in gynecologic patients; however, as far as elderly patients are concerned, its incidence is 13.6% [3]. The most common cause of pyometra is malignant diseases of genital tract and the consequences of their treatment (radiotherapy. Other causes are benign tumors like leiomyoma, endometrial polyps, senile cervicitis, cervical occlusion after surgery, puerperal infections, and congenital cervical anomalies. Spontaneous rupture of the uterus is an extremely rare complication of pyometra. To our knowledge, only 21 cases of spontaneous perforation of pyometra have been reported in English literature since 1980. This paper reports an additional case of spontaneous uterine rupture.

  3. Photofission cross section and fissility of pre-actinide and intermediate-mass nuclei by 120- and 145-MeV Compton backscattered photons

    Energy Technology Data Exchange (ETDEWEB)

    Terranova, M.L. [Istituto Nazionale di Fisica Nucleare, Rome (Italy); Kezerashvili, G. Ya.; Milov, A.M. [Russian Academy of Sciences, Moscow (Russian Federation). Budker Inst. of Nuclear Physics] [and others

    1997-09-01

    Cross section measurements for photofission induced in {sup 209} Bi, {sup natP}b, {sup 197} Au, {sup nat} Pt, nat{sub w}, {sup 181} Ta, {sup 51} V and {sup nat} Ti by 120- and 145-MeV quasi-monochromatic photon beams have been performed at the ROKK-1M facility (BINP, Novosibirsk). The fission yields have been obtained using Makrofol sheets as solid-state fission track detectors. Nuclear fissility values have been deduced on the basis of Levinger`s modified quasi-deuteron model of photonuclear interaction, and compared with available literature data. The trend of fissility in the 60-145 MeV energy range has been analysed for various target nuclei as function of energy and of parameter Z{sup 2}/A. (author) 30 refs., 6 figs., 4 tabs.

  4. Impact of intravenous immunoglobulin on peripheral blood natural killer cells in women with recurrent spontaneous abortion%复发性流产患者注射免疫球蛋白对NK细胞的影响

    Institute of Scientific and Technical Information of China (English)

    滕奔琦; 张媛; 魏方; 李玲; 范建辉

    2013-01-01

    Objective To explore the impact of intravenous immunoglobulin on peripheral blood natural killer (NK) cells in women with recurrent spontaneous abortion (RSA).Methods Of 38 patients with RSA who had been hospitalized during the period of January 2011 to June 2012,18 patients received intravenous immunoglobulin (study group) while the rest 20 who refused to receive immunoglobulin were assigned to a control group.Peripheral NK cell cytotoxicity and rate of NK cells in all types of lymphocytes were detected before and after treatment by flow cytometry.Results NK cell cytotoxicity was(22.4 + 7.9)% in the study group and (21.7 ± 8.1)% in the control group before treatment,was (15.0 ± 4.2)% in the study group and (25.6 ± 7.9)% in the control group after treatment.Before treatment,the rate of NK cell was (25.1 ± 9.4) % in the study group and (24.0 ± 9.0) % in the control group,while after treatment it was (26.2 ± 8.7) % in the study group and (23.6 ± 6.8) % in the control group.NK cell c.vtotoxicity but not the rate of NK cell was significantly reduced (P<0.05) in the study group.After treatment,NK cell cytotoxicity and the rate of NK cell did not differ significantly (P>0.05).88.9% of the patients in the study group but 55.0% of the patients in the control group had pregnancy duration of longer than 24 weeks after tocolytic treatment (P<0.05).Conclusions Intravenous immunoglobulin can reduce NK cell cytotoxicity,leading to an increase in the success rate of miscarriage prevention in patients with recurrent spontaneous abortion.%目的 探讨复发性流产(recurrent spontaneous abortion,RSA)患者静脉滴注免疫球蛋白对其外周血NK细胞的影响.方法 2011年1月至2012年6月在我院住院的RSA患者共38例.其中18例静脉滴注免疫球蛋白(IVIG)治疗,作为研究组;20例不同意使用免疫球蛋白治疗的RSA患者作为对照组.比较两组患者外周血NK细胞毒性及NK细胞在所有

  5. Spontaneous Atraumatic Mediastinal Hemorrhage

    Directory of Open Access Journals (Sweden)

    Morkos Iskander BSc, BMBS, MRCS, PGCertMedEd

    2013-04-01

    Full Text Available Spontaneous atraumatic mediastinal hematomas are rare. We present a case of a previously fit and well middle-aged lady who presented with acute breathlessness and an increasing neck swelling and spontaneous neck bruising. On plain chest radiograph, widening of the mediastinum was noted. The bruising was later confirmed to be secondary to mediastinal hematoma. This life-threatening diagnostic conundrum was managed conservatively with a multidisciplinary team approach involving upper gastrointestinal and thoracic surgeons, gastroenterologists, radiologists, intensivists, and hematologists along with a variety of diagnostic modalities. A review of literature is also presented to help surgeons manage such challenging and complicated cases.

  6. Spontaneous generation in medieval Jewish philosophy and theology.

    Science.gov (United States)

    Gaziel, Ahuva

    2012-01-01

    The concept of life forms emerging from inanimate matter--spontaneous generation--was widely accepted until the nineteenth century. Several medieval Jewish scholars acknowledged this scientific theory in their philosophical and religious contemplations. Quite interestingly, it served to reinforce diverse, or even opposite, theological conclusions. One approach excluded spontaneously-generated living beings form the biblical account of creation or the story of the Deluge. Underlying this view is an understanding that organisms that generate spontaneously evolve continuously in nature and, therefore, do not require divine intervention in their formation or survival during disastrous events. This naturalistic position reduces the miraculous dimension of reality. Others were of the opinion that spontaneous generation is one of the extraordinary marvels exhibited in this world and, accordingly, this interpretation served to accentuate the divine aspect of nature. References to spontaneous generation also appear in legal writings, influencing practical applications such as dietary laws and actions forbidden on the Sabbath.

  7. Experimental Studying of the Shortest Natural Spontaneous Combustion Period of 3-1 Coal Seam of Menkeqing Coal Mine%门克庆煤矿3-1煤层最短自然发火期实验研究

    Institute of Scientific and Technical Information of China (English)

    孙喜贵; 徐长富; 姚海飞; 张群; 吴海军

    2016-01-01

    最短自然发火期是衡量煤自然发火危险性的重要指标之一。为了科学地测试煤层最短自然发火期,以门克庆3-1煤层为研究对象,利用煤的绝热氧化反应装置,测试了煤样升温过程中各种气体的生成量,确定了3-1煤的交叉点温度,并根据生成的CO与CO2键能值计算氧化升温过程中的放热量,再根据差示扫描量热实验测定了不同温度时煤的比热容,进而分段计算达到交叉点温度所需要的时间。结果表明:门克庆煤矿3-1煤自燃倾向性等级属于I类,最短自然发火期43d,为煤矿制定有效防灭火措施提供了依据。%The shortest natural spontaneous combustion was an important indicator of natural spontaneous combustion risk evalua-tion. In order to test the shortest natural spontaneous combustion scientific, it taking 3-1 coal seam of Menkeqing coal seam as studying object, and isolated heat oxidation reaction device was utilized, the production of all kinds gases were test during temperature rise pe-riod, and the intersection temperature of 3-1 coal seam was confirmed, and the heat release during oxidation temperature rise period was calculated by chemical bond energy value of CO and CO2 that generated, and the specific heat capacity of coal in different temper-ature was test on the basis of DSC, and then the lasting time that reached intersection point temperature was calculated partition. The results showed that the natural spontaneous combustion tendency was belong I classification, the shortest natural spontaneous combus-tion period was 43d, it references for valid fire precaution formulated of coal mine.

  8. Analysis of Electron and Antineutrino Energy Spectra from Fissile Samples under Irradiation based on Gross Theory of Beta-decay

    Science.gov (United States)

    Yoshida, T.; Tachibana, T.; Chiba, S.

    2016-06-01

    We applied the gross theory of β-decay to calculate the reactor electron and antineutrino ({{{bar ν }}{e}}) spectra emitted from 235,238U and 239,241Pu by summing up all the contributions from a large number of decaying fission-products (FPs). We make it clear what kinds of transition types and FP nuclides are important to shape the lepton spectra. After taking the ambiguity in the current data for fission yields and Qβ-values into account, we suggested a possibility that the high-energy part of the widely referred electron-spectra by Schreckenbach et al., almost only one experimental data set available now, might possibly be too low. Arguments on a special role of the odd(Z)-odd(N) nuclides and on the consistency between U-238 and other fissiles in the experimental data lead to the importance of a new and independent measurement of electron energy spectra which could be converted into the reactor {{{bar ν }}{e}} spectra.

  9. Spontaneous rib fractures.

    Science.gov (United States)

    Katrancioglu, Ozgur; Akkas, Yucel; Arslan, Sulhattin; Sahin, Ekber

    2015-07-01

    Other than trauma, rib fracture can occur spontaneously due to a severe cough or sneeze. In this study, patients with spontaneous rib fractures were analyzed according to age, sex, underlying pathology, treatment, and complications. Twelve patients who presented between February 2009 and February 2011 with spontaneous rib fracture were reviewed retrospectively. The patients' data were evaluated according to anamnesis, physical examination, and chest radiographs. The ages of the patients ranged from 34 to 77 years (mean 55.91 ± 12.20 years), and 7 (58.4%) were male. All patients had severe cough and chest pain. The fractures were most frequently between 4th and 9th ribs; multiple rib fractures were detected in 5 (41.7%) patients. Eight (66.7%) patients had chronic obstructive pulmonary disease, 2 (16.7%) had bronchial asthma, and 2 (16.7%) had osteoporosis. Bone densitometry revealed a high risk of bone fracture in all patients. Patients with chronic obstructive pulmonary disease or bronchial asthma had been treated with high-dose steroids for over a year. Spontaneous rib fracture due to severe cough may occur in patients with osteoporosis, chronic obstructive pulmonary disease, or bronchial asthma, receiving long-term steroid therapy. If these patients have severe chest pain, chest radiography should be performed to check for bone lesions. © The Author(s) 2015.

  10. Spontaneous transverse colon volvulus.

    Science.gov (United States)

    Sana, Landolsi; Ali, Gassara; Kallel, Helmi; Amine, Baklouti; Ahmed, Saadaoui; Ali, Elouer Mohamed; Wajdi, Chaeib; Saber, Mannaï

    2013-01-01

    We report a case of spontaneous transverse colon volvulus in a young healthy woman. It constitutes an unusual case since it occurred in a young healthy woman with a subacute onset and no aetiological factor has been found. Its diagnosis is still challenging. Prompt recognition with emergency intervention constitutes the key to successful outcome.

  11. [Spontaneous bacterial peritonitis].

    Science.gov (United States)

    Velkey, Bálint; Vitális, Eszter; Vitális, Zsuzsanna

    2017-01-01

    Spontaneous bacterial peritonitis occurs most commonly in cirrhotic patients with ascites. Pathogens get into the circulation by intestinal translocation and colonize in peritoneal fluid. Diagnosis of spontaneous bacterial peritonitis is based on elevated polymorphonuclear leukocyte count in the ascites (>0,25 G/L). Ascites culture is often negative but aids to get information about antibiotic sensitivity in positive cases. Treatment in stable patient can be intravenous then orally administrated ciprofloxacin or amoxicillin/clavulanic acid, while in severe cases intravenous III. generation cephalosporin. Nosocomial spontaneous bacterial peritonitis often caused by Gram-positive bacteria and multi-resistant pathogens can also be expected thus carbapenem should be the choice of the empiric treatment. Antibiotic prophylaxis should be considered. Norfloxacin is used most commonly, but changes are expected due to increase in quinolone resistance. As a primary prophylaxis, a short-term antibiotic treatment is recommended after gastrointestinal bleeding for 5 days, while long-term prophylaxis is for patients with low ascites protein, and advanced disease (400 mg/day). Secondary prophylaxis is recommended for all patients recovered from spontaneous bacterial peritonitis. Due to increasing antibiotic use of antibiotics prophylaxis is debated to some degree. Orv. Hetil., 2017, 158(2), 50-57.

  12. On spontaneous scalarization

    CERN Document Server

    Salgado, M; Nucamendi, U; Salgado, Marcelo; Sudarsky, Daniel; Nucamendi, Ulises

    1998-01-01

    We study in the physical frame the phenomenon of spontaneous scalarization that occurs in scalar-tensor theories of gravity for compact objects. We discuss the fact that the phenomenon occurs exactly in the regime where the Newtonian analysis indicates it should not. Finally we discuss the way the phenomenon depends on the equation of state used to describe the nuclear matter.

  13. Spontaneous shrinkage of vestibular schwannoma

    Directory of Open Access Journals (Sweden)

    Rossana Romani

    2016-01-01

    Conclusion: Early WWR management can be associated with spontaneous shrinkage of VS over time. Prospective clinical study of larger numbers of such cases using the UK VS database may help to identify predictive factors for the spontaneous regression of VS.

  14. Spontaneous healing of spontaneous coronary artery dissection.

    Science.gov (United States)

    Almafragi, Amar; Convens, Carl; Heuvel, Paul Van Den

    2010-01-01

    Spontaneous coronary artery dissection (SCAD) is a rare cause of acute coronary syndrome and sudden cardiac death. It should be suspected in every healthy young woman without cardiac risk factors, especially during the peripartum or postpartum periods. It is important to check for a history of drug abuse, collagen vascular disease or blunt trauma of the chest. Coronary angiography is essential for diagnosis and early management. We wonder whether thrombolysis might aggravate coronary dissection. All types of treatment (medical therapy, percutaneous intervention or surgery) improve the prognosis without affecting survival times if used appropriately according to the clinical stability and the angiographic features of the involved coronary arteries. Prompt recognition and targeted treatment improve outcomes. We report a case of SCAD in a young female free of traditional cardiovascular risk factors, who presented six hours after thrombolysis for ST elevation myocardial infarction. Coronary angiography showed a dissection of the left anterior descending and immediate branch. She had successful coronary artery bypass grafting, with complete healing of left anterior descending dissection.

  15. The spontaneous market order and evolution.

    Science.gov (United States)

    Beck, Naomi

    2016-08-01

    Darwin's theory of natural selection and the idea of a spontaneous order share a fundamental feature: the claim that apparent design or order do not necessarily imply a designer or rational planning. But they also present important differences, which touch upon central questions such as the evolution of morality, the role of human agency in social evolution, the existence (or not) of directionality in undesigned processes, and the presence (nor not) of a providential element in evolutionary accounts. In this article, I explore these themes and probe the relationship between the notion of a spontaneous order and the theory of evolution by natural selection. The reflections of Nobel laureate in economics, F.A. von Hayek, provide the beginning and endpoint in this voyage, for they constitute the most pronounced effort to develop a full-fledged theory combining evolution and economics in recent times. But along the way, I also investigate the influence of classical political economy on Darwin's thought, primarily that of Adam Smith, and consider the reasons for which Darwin did not refer to Smith when discussing the principle of natural selection in The Origin of Species. I conclude that the spontaneous order, as understood by Hayek, and evolution by natural selection constitute two disparate concepts.

  16. Spontaneous Symmetry Probing

    CERN Document Server

    Nicolis, Alberto

    2011-01-01

    For relativistic quantum field theories, we consider Lorentz breaking, spatially homogeneous field configurations or states that evolve in time along a symmetry direction. We dub this situation "spontaneous symmetry probing" (SSP). We mainly focus on internal symmetries, i.e. on symmetries that commute with the Poincare group. We prove that the fluctuations around SSP states have a Lagrangian that is explicitly time independent, and we provide the field space parameterization that makes this manifest. We show that there is always a gapless Goldstone excitation that perturbs the system in the direction of motion in field space. Perhaps more interestingly, we show that if such a direction is part of a non-Abelian group of symmetries, the Goldstone bosons associated with spontaneously broken generators that do not commute with the SSP one acquire a gap, proportional to the SSP state's "speed". We outline possible applications of this formalism to inflationary cosmology.

  17. Spontaneous nephrocutaneous fistula

    Directory of Open Access Journals (Sweden)

    Alberto A. Antunes

    2004-08-01

    Full Text Available Spontaneous renal fistula to the skin is rare. The majority of cases develop in patients with antecedents of previous renal surgery, renal trauma, renal tumors, and chronic urinary tract infection with abscess formation. We report the case of a 62-year old woman, who complained of urine leakage through the skin in the lumbar region for 2 years. She underwent a fistulography that revealed drainage of contrast agent to the collecting system and images suggesting renal lithiasis on this side. The patient underwent simple nephrectomy on this side and evolved without intercurrences in the post-operative period. Currently, the occurrence of spontaneous renal and perirenal abscesses is extremely rare, except in patients with diabetes, neoplasias and immunodepression in general.

  18. Spontaneous Pneumomediastinum in Labor

    Science.gov (United States)

    Benlamkadem, Said; Labib, Smael; Harandou, Mustapha

    2017-01-01

    Spontaneous pneumomediastinum and subcutaneous emphysema also known as Hamman's syndrome is a very rare complication of labor that is often related to the valsalva maneuver during the labor. In most case, Hamman's syndrome is a self-limiting condition, rarely complicated unless there are underlying respiratory diseases. Chest X-ray can be a useful early diagnostic technique in severe clinical presentation. We report an uneventful pregnancy in a primigravid parturient, which was complicated in the late second stage of labor by the development of subcutaneous emphysema, pneumomediastinum, and mild pneumothorax. Spontaneous recovery occurred after four days of conservative management. This condition shows the major interest of labor analgesia especially locoregional techniques. PMID:28316849

  19. Spontaneous Rupture of Pyometra

    Directory of Open Access Journals (Sweden)

    Fatemeh Mallah

    2013-01-01

    Full Text Available Spontaneous perforation is a very rare complication of pyometra. The clinical findings of perforated pyometra are similar to perforation of the gastrointestinal tract and other causes of acute abdomen. In most cases, a correct and definite diagnosis can be made only by laparotomy. We report two cases of diffuse peritonitis caused by spontaneous perforated pyometra. The first case is a 78-year-old woman with abdominal pain for which laparotomy was performed because of suspected incarcerated hernia. The second case is a 61-year-old woman with abdominal pain for which laparotomy was performed because of symptoms of peritonitis. At laparotomy of both cases, 1 liter of pus with the source of uterine was found in the abdominal cavity. The ruptured uterine is also detected. More investigations revealed no malignancy as the reason of the pyometra.

  20. [Spontaneous spinal cord herniation].

    Science.gov (United States)

    Rivas, J J; de la Lama, A; Gonza Lez, P; Ramos, A; Zurdo, M; Alday, R

    2004-10-01

    Spontaneous spinal cord herniation through a dural defect is an unusual condition. This entity has been probably underestimated before the introduction of MRI. We report a case of a 49-year-old man with a progressive Brown-Sequard syndrome. MRI and CT myelogram showed a ventrally displaced spinal cord at level T6-T7 and expansion of the posterior subarachnoid space. Through a laminectomy, a spinal cord herniation was identified and reduced. The anterior dural defect was repaired with a patch of lyophilized dura. The patient recovered muscle power but there was no improvement of the sensory disturbance. The diagnosis of spontaneous spinal cord herniation must be considered when progressive myelopathy occurs in middle-aged patients, without signs of spinal cord compression and typical radiological findings. Surgical treatment may halt the progressive deficits and even yield improvement in many cases.

  1. Spontaneous Perforation of Pyometra.

    Science.gov (United States)

    Sharma, Nalini; Singh, Ahanthem Santa; Bhaphiralyne, Wankhar

    2016-04-01

    Pyometra is collection of purulent material which occurs when there is interference with its normal drainage. It is an uncommon condition with incidence of 0.1 to 0.5% of all gynecological patients. Spontaneous rupture of uterus is an extremely rare complication of pyometra. A 65-year-old lady presented with pain abdomen and purulent vaginal discharge. Preoperative diagnosis of pyometra was made by magnetic resonance imaging (MRI). Laparotomy followed by peritoneal lavage and repair of perforation was performed. Although spontaneously perforated pyometra is rare, the condition must be borne in mind with regard to elderly women with acute abdominal pain. Preoperative diagnosis of perforated pyometra is absolutely essential. Computed tomography (CT) and MRI are diagnostic tools. In selected cases conservative approach at surgery can be opted.

  2. Spontaneous Rupture of Pyometra

    Science.gov (United States)

    Mallah, Fatemeh; Eftekhar, Tahere; Naghavi-Behzad, Mohammad

    2013-01-01

    Spontaneous perforation is a very rare complication of pyometra. The clinical findings of perforated pyometra are similar to perforation of the gastrointestinal tract and other causes of acute abdomen. In most cases, a correct and definite diagnosis can be made only by laparotomy. We report two cases of diffuse peritonitis caused by spontaneous perforated pyometra. The first case is a 78-year-old woman with abdominal pain for which laparotomy was performed because of suspected incarcerated hernia. The second case is a 61-year-old woman with abdominal pain for which laparotomy was performed because of symptoms of peritonitis. At laparotomy of both cases, 1 liter of pus with the source of uterine was found in the abdominal cavity. The ruptured uterine is also detected. More investigations revealed no malignancy as the reason of the pyometra. PMID:24024054

  3. Spontaneous bacterial peritonitis

    OpenAIRE

    Al Amri Saleh

    1995-01-01

    Spontaneous bacterial peritonitis (SBP) is an infection of the ascitic fluid without obvious intra-abdominal source of sepsis; usually complicates advanced liver disease. The pathogenesis of the disease is multifactorial: low ascitic protein-content, which reflects defi-cient ascitic fluid complement and hence, reduced opsonic activity is thought to be the most important pathogenic factor. Frequent and prolonged bacteremia has been considered as another pertinent cause of SBP. This disease is...

  4. [Spontaneous bilateral Petit hernia].

    Science.gov (United States)

    Fontoura, Rodrigo Dias; Araújo, Emerson Silveira de; Oliveira, Gustavo Alves de; Sarmenghi Filho, Deolindo; Kalil, Mitre

    2011-01-01

    Petit's lumbar hernia is an uncommon defect of the posterior abdominal wall that represents less than 1% of all abdominal wall hernias. It is more often unilateral and founded in young females, rarely containing a real herniated sac. There are two different approaches to repair: laparoscopy and open surgery. The goal of this article is to report one case of spontaneous bilateral lumbar Petit's hernia treated with open surgery.

  5. Spontaneous Flapping Flight

    Science.gov (United States)

    Vandenberghe, Nicolas; Zhang, Jun; Childress, Stephen

    2004-11-01

    As shown in an earlier work [Vandenberghe, et. al. JFM, Vol 506, 147, 2004], a vertically flapping wing can spontaneously move horizontally as a result of symmetry breaking. In the current experimental study, we investigate the dependence of resultant velocity on flapping amplitude. We also describe the forward thrust generation and how the system dynamically selects a Strouhal number by balancing fluid and body forces. We further compare our model system with examples of biological locomotion, such as bird flight and fish swimming.

  6. Spontaneous Perforation of Pyometra

    OpenAIRE

    Sharma, Nalini; Singh, Ahanthem Santa; Bhaphiralyne, Wankhar

    2016-01-01

    Pyometra is collection of purulent material which occurs when there is interference with its normal drainage. It is an uncommon condition with incidence of 0.1 to 0.5% of all gynecological patients. Spontaneous rupture of uterus is an extremely rare complication of pyometra. A 65-year-old lady presented with pain abdomen and purulent vaginal discharge. Preoperative diagnosis of pyometra was made by magnetic resonance imaging (MRI). Laparotomy followed by peritoneal lavage and repair of perfor...

  7. Spontaneous spinal epidural abscess.

    LENUS (Irish Health Repository)

    Ellanti, P

    2011-10-01

    Spinal epidural abscess is an uncommon entity, the frequency of which is increasing. They occur spontaneously or as a complication of intervention. The classical triad of fever, back pain and neurological symptoms are not always present. High index of suspicion is key to diagnosis. Any delay in diagnosis and treatment can have significant neurological consequences. We present the case of a previously well man with a one month history of back pain resulting from an epidural abscess.

  8. A treaty on the cutoff of fissile material for nuclear weapons - What to cover? How to verify?

    Energy Technology Data Exchange (ETDEWEB)

    Schaper, A. [Peace Research Inst., Frankfurt (Germany)

    1998-07-01

    Since 1946, a cutoff has been proposed. In 1993, the topic was placed on the agenda of the CD. The establishment of an Ad Hoc Committee in the CD with a mandate to negotiate a fissile material cutoff treaty struggled with difficulties for more than a year. The central dispute was whether the mandate should refer to existing un-safeguarded stockpiles. The underlying conflict of the CTBT negotiations can be summarized as nuclear disarmament versus nuclear nonproliferation The same conflict is now blocking progress with FMCT negotiations in the CD. At the center of technical proliferation concerns is direct use material that can be used for nuclear warheads without any further enrichment or reprocessing. Those materials are plutonium and highly enriched uranium (HEU). A broader category of materials is defined as all those containing any fissile isotopes, called special fissionable materials. In order ta verify that no direct use materials are abused for military purposes, also special fissionable materials must be controlled. An even broader category is simply called nuclear materials. Pu and HEU can be distinguished into the following categories of utilisation: 1. military direct use material in operational nuclear weapons and their logistics pipeline, 2. military direct use material held in reserve for military purposes, in assembled weapons or in other forms, 3. military direct use material withdrawn from dismantled weapons, 4. military direct use material considered excess and designated for transfer into civilian use, 5. military direct use material considered excess and declared for transfer into civilian use, 6. direct use material currently in reactors or their logistics pipelines and storages, and 7. irradiated Pu and HEU in spent fuel from reactors, or in vitrified form for final disposal. Large quantities of materials are neither inside weapons nor declared excess. So far, there are no legal obligations for NWS for limitations, declarations, or

  9. Spontaneous Thigh Compartment Syndrome

    Directory of Open Access Journals (Sweden)

    Khan, Sameer K

    2011-02-01

    Full Text Available A young man presented with a painful and swollen thigh, without any history of trauma, illness, coagulopathic medication or recent exertional exercise. Preliminary imaging delineated a haematoma in the anterior thigh, without any fractures or muscle trauma. Emergent fasciotomies were performed. No pathology could be identified intra-operatively, or on follow-up imaging. A review of thigh compartment syndromes described in literature is presented in a table. Emergency physicians and traumatologists should be cognisant of spontaneous atraumatic presentations of thigh compartment syndrome, to ensure prompt referral and definitive management of this limb-threatening condition. [West J Emerg Med. 2011;12(1:134-138].

  10. Spontaneous bacterial peritonitis

    Directory of Open Access Journals (Sweden)

    Al Amri Saleh

    1995-01-01

    Full Text Available Spontaneous bacterial peritonitis (SBP is an infection of the ascitic fluid without obvious intra-abdominal source of sepsis; usually complicates advanced liver disease. The pathogenesis of the disease is multifactorial: low ascitic protein-content, which reflects defi-cient ascitic fluid complement and hence, reduced opsonic activity is thought to be the most important pathogenic factor. Frequent and prolonged bacteremia has been considered as another pertinent cause of SBP. This disease is associated with high mortality and recurrence. Therefore, orompt recognition and institution of therapy and plan of prophylaxis is vital.

  11. Spontaneously broken mass

    CERN Document Server

    Endlich, Solomon; Penco, Riccardo

    2013-01-01

    The Galilei group involves mass as a central charge. We show that the associated superselection rule is incompatible with the observed phenomenology of superfluid helium 4: this is recovered only under the assumption that mass is spontaneously broken. This remark is somewhat immaterial for the real world, where the correct space-time symmetries are encoded by the Poincar\\'e group, which has no central charge. Yet it provides an explicit example of how superselection rules can be experimentally tested. We elaborate on what conditions must be met for our ideas to be generalizable to the relativistic case of the integer/half-integer angular momentum superselection rule.

  12. Control of radioactive wastes and coupling of neutron/gamma measurements: use of radiative capture for the correction of matrix effects that penalize the fissile mass measurement by active neutron interrogation; Controle des dechets radioactifs et couplage de mesures neutron/gamma: exploitation de la capture radiative pour corriger les effets de matrice penalisant la mesure de la masse fissile par interrogation neutronique active

    Energy Technology Data Exchange (ETDEWEB)

    Loche, F

    2006-10-15

    In the framework of radioactive waste drums control, difficulties arise in the nondestructive measurement of fissile mass ({sup 235}U, {sup 239}Pu..) by Active Neutron Interrogation (ANI), when dealing with matrices containing materials (Cl, H...) influencing the neutron flux. The idea is to use the neutron capture reaction (n,{gamma}) to determine the matrix composition to adjust the ANI calibration coefficient value. This study, dealing with 118 litres, homogeneous drums of density less than 0,4 and composed of chlorinated and/or hydrogenated materials, leads to build abacus linking the {gamma} ray peak areas to the ANI calibration coefficient. Validation assays of these abacus show a very good agreement between the corrected and true fissile masses for hydrogenated matrices (max. relative standard deviation: 23 %) and quite good for chlorinated and hydrogenated matrices (58 %). The developed correction method improves the measured values. It may be extended to 0,45 density, heterogeneous drums. (author)

  13. Photonic Crystals-Inhibited Spontaneous Emission: Optical Antennas-Enhanced Spontaneous Emission

    Science.gov (United States)

    Yablonovitch, Eli

    Photonic crystals are also part of everyday technological life in opto-electronic telecommunication devices that provide us with internet, cloud storage, and email. But photonic crystals have also been identified in nature, in the coloration of peacocks, parrots, chameleons, butterflies and many other species.In spite of its broad applicability, the original motivation of photonic crystals was to create a ``bandgap'' in which the spontaneous emission of light would be inhibited. Conversely, the opposite is now possible. The ``optical antenna'' can accelerate spontaneous emission. Over 100 years after the radio antenna, we finally have tiny ``optical antennas'' which can act on molecules and quantum dots. Employing optical antennas, spontaneous light emission can become faster than stimulated emission.

  14. Experimental Demonstration of Spontaneous Chirality in a Nonlinear Microresonator

    Science.gov (United States)

    Cao, Qi-Tao; Wang, Heming; Dong, Chun-Hua; Jing, Hui; Liu, Rui-Shan; Chen, Xi; Ge, Li; Gong, Qihuang; Xiao, Yun-Feng

    2017-01-01

    Chirality is an asymmetric property widely found in nature. Here, we propose and demonstrate experimentally the spontaneous emergence of chirality in an on-chip ultrahigh-Q whispering-gallery microresonator, without broken parity or time-reversal symmetry. This counterintuitive effect arises due to the inherent Kerr-nonlinearity-modulated coupling between clockwise and counterclockwise propagating waves. Above an input threshold of a few hundred microwatts, the initial chiral symmetry is broken spontaneously, and the counterpropagating output ratio exceeds 20 ∶1 with bidirectional inputs. The spontaneous chirality in an on-chip microresonator holds great potential in studies of fundamental physics and applied photonic devices.

  15. Quantum Spontaneous Stochasticity

    CERN Document Server

    Eyink, Gregory L

    2015-01-01

    The quantum wave-function of a massive particle with small initial uncertainties (consistent with the uncertainty relation) is believed to spread very slowly, so that the dynamics is deterministic. This assumes that the classical motions for given initial data are unique. In fluid turbulence non-uniqueness due to "roughness" of the advecting velocity field is known to lead to stochastic motion of classical particles. Vanishingly small random perturbations are magnified by Richardson diffusion in a "nearly rough" velocity field so that motion remains stochastic as the noise disappears, or classical spontaneous stochasticity, . Analogies between stochastic particle motion in turbulence and quantum evolution suggest that there should be quantum spontaneous stochasticity (QSS). We show this for 1D models of a particle in a repulsive potential that is "nearly rough" with $V(x) \\sim C|x|^{1+\\alpha}$ at distances $|x|\\gg \\ell$ , for some UV cut-off $\\ell$, and for initial Gaussian wave-packet centered at 0. We consi...

  16. Spontaneous regression of lung metastasis from osteosarcoma: a case report.

    Science.gov (United States)

    Bacci, Gaetano; Palmerini, Emanuela; Staals, Eric L; Ferrari, Stefano; Battaglia, Milva; Longhi, Alessandra; Bertoni, Franco; Briccoli, Antonio

    2008-01-01

    A case of spontaneous regression of a pulmonary metastasis from high-grade osteosarcoma is reported. The metastasis developed 5 years after chemotherapy and amputation for a distal femur osteosarcoma. The sarcomatous nature of the lesion was histologically confirmed. No treatment was attempted owing to the patient's refusal. The patient was followed up every 3 months and a spontaneous regression of the lesion was documented. Seven years after the diagnosis of lung metastases, no pulmonary nodules or other signs of relapse are present.

  17. Optical Antenna Enhanced Spontaneous Emission in Semiconductors

    Science.gov (United States)

    Messer, Kevin James

    Optical antennas can be used to dramatically increase the rate that semiconductors spontaneously emit photons. While traditional LEDs are limited in bandwidth due to the "slow" rate of spontaneous emission, antenna-enhanced LEDs have the potential to be a fast, efficient, nanoscale light emitter. Traditionally, lasers have dominated LEDs as the emitter in optical interconnects due to a 200x speed advantage of stimulated emission over spontaneous emission. This paradigm may be reversed by coupling LEDs to optical antennas. In fact, antenna enhanced spontaneous emission can be faster than the fastest stimulated emission. Spontaneous emission originates from dipole fluctuations within the emitting material. The size of these fluctuations is much less than the wavelength of light emission, which leads to slow spontaneous emission. Coupling the material to an optical antenna corrects the size mismatch and improves the rate of radiation. An optical antenna circuit model is developed to predict the degree to which spontaneous emission can be enhanced. The circuit model presented in this dissertation shows that enhancement over 1000x is possible while still maintaining greater than 50% efficiency. The circuit model provides insight how to design optical antennas for coupling to dipole sources, for maximum enhancement, and for high efficiency. A method for incorporating the anomalous skin effect, often overlooked in metal optics, is provided. While FDTD/FEM simulations cannot include this effect due to its nonlocal nature, its impact can be examined through the use of the optical antenna circuit model. Analysis of the tradeoff between achieving large spontaneous emission enhancement and maintaining high efficiency leads to an ideal antenna feedgap size of 10nm. Experimental demonstration of spontaneous emission enhancement from InP coupled to an arch-dipole antenna is presented. Photoluminescence measurements show light emission from antenna-coupled InP over bare InP ridges

  18. Fissile Material Disposition Program: Deep borehole disposal Facility PEIS date input report for immobilized disposal. Immobilized disposal of plutonium in coated ceramic pellets in grout with canisters. Version 3.0

    Energy Technology Data Exchange (ETDEWEB)

    Wijesinghe, A.M.; Shaffer, R.J.

    1996-01-15

    Following President Clinton`s Non-Proliferation Initiative, launched in September, 1993, an Interagency Working Group (IWG) was established to conduct a comprehensive review of the options for the disposition of weapons-usable fissile materials from nuclear weapons dismantlement activities in the United States and the former Soviet Union. The IWG review process will consider technical, nonproliferation, environmental budgetary, and economic considerations in the disposal of plutonium. The IWG is co-chaired by the White House Office of Science and Technology Policy and the National Security Council. The Department of Energy (DOE) is directly responsible for the management, storage, and disposition of all weapons-usable fissile material. The Department of Energy has been directed to prepare a comprehensive review of long-term options for Surplus Fissile Material (SFM) disposition, taking into account technical, nonproliferation, environmental, budgetary, and economic considerations.

  19. Spontaneous Coronary Artery Dissection.

    Science.gov (United States)

    Tweet, Marysia S; Gulati, Rajiv; Hayes, Sharonne N

    2016-07-01

    Spontaneous coronary artery dissection is an important etiology of nonatherosclerotic acute coronary syndrome, myocardial infarction, and sudden death. Innovations in the catheterization laboratory including optical coherence tomography and intravascular ultrasound have enhanced the ability to visualize intimal disruption and intramural hematoma associated with SCAD. Formerly considered "rare," these technological advances and heightened awareness suggest that SCAD is more prevalent than prior estimates. SCAD is associated with female sex, young age, extreme emotional stress, or extreme exertion, pregnancy, and fibromuscular dysplasia. The clinical characteristics and management strategies of SCAD patients are different than for atherosclerotic heart disease and deserve specific consideration. This review will highlight recent discoveries about SCAD as well as describe current efforts to elucidate remaining gaps in knowledge.

  20. Spontaneous aortocaval fistula.

    Directory of Open Access Journals (Sweden)

    Rajmohan B

    2002-07-01

    Full Text Available Spontaneous aortocaval fistula is rare, occurring only in 4% of all ruptured abdominal aortic aneurysms. The physical signs can be missed but the presence of low back pain, palpable abdominal aortic aneurysm, machinery abdominal murmur and high-output cardiac failure unresponsive to medical treatment should raise the suspicion. Pre-operative diagnosis is crucial, as adequate preparation has to be made for the massive bleeding expected at operation. Successful treatment depends on management of perioperative haemodynamics, control of bleeding from the fistula and prevention of deep vein thrombosis and pulmonary embolism. Surgical repair of an aortocaval fistula is now standardised--repair of the fistula from within the aneurysm (endoaneurysmorraphy followed by prosthetic graft replacement of the aneurysm. A case report of a 77-year-old woman, initially suspected to have unstable angina but subsequently diagnosed to have an aortocaval fistula and surgically treated successfully, is presented along with a review of literature.

  1. Screening for spontaneous preterm birth

    NARCIS (Netherlands)

    van Os, M.A.; van Dam, A.J.E.M.

    2015-01-01

    Preterm birth is the most important cause of perinatal morbidity and mortality worldwide. In this thesis studies on spontaneous preterm birth are presented. The main objective was to investigate the predictive capacity of mid-trimester cervical length measurement for spontaneous preterm birth in a l

  2. Pregnancy outcome following spontaneous abortions

    Directory of Open Access Journals (Sweden)

    Swati Agrawal

    2015-12-01

    Conclusions: Previous history of spontaneous abortion is associated with adverse pregnancy outcome. There is increased risk of abortion, preterm delivery, need for caesarean sections and fetal loss in cases of previous spontaneous abortions. These complications and fetal loss can be reduced by booking the patients and giving due antenatal care. [Int J Reprod Contracept Obstet Gynecol 2015; 4(6.000: 1891-1893

  3. Screening for spontaneous preterm birth

    NARCIS (Netherlands)

    van Os, M.A.; van Dam, A.J.E.M.

    2015-01-01

    Preterm birth is the most important cause of perinatal morbidity and mortality worldwide. In this thesis studies on spontaneous preterm birth are presented. The main objective was to investigate the predictive capacity of mid-trimester cervical length measurement for spontaneous preterm birth in a

  4. Spontaneous pneumomediastinum and Ecstasy abuse.

    OpenAIRE

    Pittman, J A; Pounsford, J C

    1997-01-01

    Ecstasy is an illegal recreationally used drug. A case of a young woman who had taken this drug and was found to have a spontaneous pneumomediastinum is reported. The association of spontaneous pneumomediastinum with drug abuse is discussed. The possible mechanism for this complication of Ecstasy, which has not been previously reported, is discussed.

  5. Shared risk aversion in spontaneous and induced abortion

    DEFF Research Database (Denmark)

    Catalano, Ralph; Bruckner, Tim A.; Karasek, Deborah

    2016-01-01

    STUDY QUESTION: Does the incidence of spontaneous abortion correlate positively over conception cohorts with the incidence of non-clinically indicated induced abortion as predicted by shared risk aversion? SUMMARY ANSWER: We find that the number of spontaneous and non-clinically indicated induced...... abortions correlates in conception cohorts, suggesting that risk aversion affects both the conscious and non-conscious mechanisms that control parturition. WHAT IS KNOWN ALREADY: Much literature speculates that natural selection conserved risk aversion because the trait enhanced Darwinian fitness. Risk...... and spontaneous abortion over time. STUDY DESIGN, SIZE, DURATION: Using data from Denmark, we test the hypothesis that monthly conception cohorts yielding unexpectedly many non-clinically indicated induced abortions also yield unexpectedly many spontaneous abortions. The 180 month test period (January 1995...

  6. Spontaneous subgaleal aerocele.

    Science.gov (United States)

    Ibe, M O N; Onu, D O; Igwe, N N

    2014-01-01

    Apart from reporting about a case of spontaneous subgaleal aerocele this paper looks at the possible causes and management also. A 35-year-old Igbo-Nigerian female, about 4 weeks post-natal, with a 10-month old steadily and gradually enlarging mass around the back of her head, including both temporal regions was referred to us. Plain skull radiographs showed air in this mass. Needle puncture produced air leading to immediate and complete flattening of the lesion. A few hours after this procedure while still in the hospital premises, she had generalized convulsions, for which she was hospitalized and treated. With no further attacks, her request for discharge the following day was granted. At the next visit, 7 days later, there was a re-accumulation, which was treated the same way as previously and with the same result. She has not reported back since then, though she was advised to visit us again in 7 day-time. This lesion should be considered when masses on the head are presented. Our health institutions should have adequate investigative facilities.

  7. Spontaneous bacterial peritonitis

    Institute of Scientific and Technical Information of China (English)

    Anastasios Koulaouzidis; Shivaram Bhat; Athar A Saeed

    2009-01-01

    Since its initial description in 1964, research has transformed spontaneous bacterial peritonitis (SBP) from a feared disease (with reported mortality of 90%) to a treatable complication of decompensated cirrhosis,albeit with steady prevalence and a high recurrence rate. Bacterial translocation, the key mechanism in the pathogenesis of SBP, is only possible because of the concurrent failure of defensive mechanisms in cirrhosis.Variants of SBP should be treated. Leucocyte esterase reagent strips have managed to shorten the 'tap-toshot' time, while future studies should look into their combined use with ascitic fluid pH. Third generation cephalosporins are the antibiotic of choice because they have a number of advantages. Renal dysfunction has been shown to be an independent predictor of mortality in patients with SBP. Albumin is felt to reduce the risk of renal impairment by improving effective intravascular volume, and by helping to bind proinflammatory molecules. Following a single episode of SBP, patients should have long-term antibiotic prophylaxis and be considered for liver transplantation.

  8. Idiopathic spontaneous pneumomediastinum: radiologic and clinical features

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi Young; Kim, Su Young; Kim, Yong Hoon; Hwang, Yoon Joon; Seo, Jung Wook; Han, Yoon Hee; Cha, Soon Joo; Hur, Gham [College of Medicine, Inje Univ., Goyang (Korea, Republic of)

    2004-07-01

    To evaluate the clinical presentations, radiological characteristics, and natural history of healthy adolescents presenting with idiopathic spontaneous pneumomediastinum. We retrospectively reviewed the simple radiographs of 14 consecutive patients (11 males) with spontaneous pneumomediastinum, who were examined over a period of 8 years, and analyzed their clinical history, radiographic findings including distribution, combined subcutaneous emphysema, mediastinal widening, pneumothorax, pleural effusion, and resolving period on follow up chest radiographs. We also obtained CT images of 7 patients for the assessment of additional information. The most common complaint at the time of presentation was chest pain and chest discomfort (8/14), followed by neck discomfort (6/14). The chest radiograph was of diagnostic value in alI cases. The main distribution of the pneumomediastinum was cervical (14/14), upper lung (13/14) and lower lung (6/14). Combined subcutaneous emphysema was observed in 6 patients. However, there were no cases of mediastinal widening, pneumothorax or pleural effusion. Complete resolution of the pneumomediastinum on the radiograph was observed after 10 days (mean 5.6), following purely conservative treatment. There was no additional information on the CT images, as compared with that on the radiographs. Idiopathic spontaneous pneumomediastinum is a benign entity that usually goes undiagnosed, but which responds very weIl to conservative treatment.

  9. Acupuncture Treatment for Spontaneous Polyhidrosis

    Institute of Scientific and Technical Information of China (English)

    WANG wei-zhi; ZHAO Liang

    2008-01-01

    objective;To compare the therapeutic effects of acupuncture and western medicine on spontaneous polyhidrosis.Methods;Acupuncture at Huatuojiaji points was used to treat 30 cases of spontaneous polyhidrosis and the western medicine was used treat 26 cases for comparison.Results;The total effective rate of the fomler was 96.7%and that of the latter 57.7%.The difference in therapeutic effect between the two groups was significant(P<0.01).Conclusion;The thempeutic effect of acupuncture at Huatuojiaji points on spontaneous polyhidrosis was better than that of western medicine.

  10. Spontaneous Baryogenesis without Baryon Isocurvature

    CERN Document Server

    De Simone, Andrea

    2016-01-01

    We propose a new class of spontaneous baryogenesis models that does not produce baryon isocurvature perturbations. The baryon chemical potential in these models is independent of the field value of the baryon-generating scalar, hence the scalar field fluctuations are blocked from propagating into the baryon isocurvature. We demonstrate this mechanism in simple examples where spontaneous baryogenesis is driven by a non-canonical scalar field. The suppression of the baryon isocurvature allows spontaneous baryogenesis to be compatible even with high-scale inflation.

  11. Cascading Multicriticality in Nonrelativistic Spontaneous Symmetry Breaking

    CERN Document Server

    Griffin, Tom; Horava, Petr; Yan, Ziqi

    2015-01-01

    Without Lorentz invariance, spontaneous global symmetry breaking can lead to multicritical Nambu-Goldstone modes with a higher-order low-energy dispersion $\\omega\\sim k^n$ ($n=2,3,\\ldots$), whose naturalness is protected by polynomial shift symmetries. Here we investigate the role of infrared divergences and the nonrelativistic generalization of the Coleman-Hohenberg-Mermin-Wagner (CHMW) theorem. We find novel cascading phenomena with large hierarchies between the scales at which the value of $n$ changes, leading to an evasion of the "no-go" consequences of the relativistic CHMW theorem.

  12. Spontaneous intraorbital hematoma: case report

    Directory of Open Access Journals (Sweden)

    Vinodan Paramanathan

    2010-12-01

    Full Text Available Vinodan Paramanathan, Ardalan ZolnourianQueen's Hospital NHS Foundation Trust, Burton on Trent, Staffordshire DE13 0RB, UKAbstract: Spontaneous intraorbital hematoma is an uncommon clinical entity seen in ophthalmology practice. It is poorly represented in the literature. Current evidence attributes it to orbital trauma, neoplasm, vascular malformations, acute sinusitis, and systemic abnormalities. A 65-year-old female presented with spontaneous intraorbital hematoma manifesting as severe ocular pains, eyelid edema, proptosis, and diplopia, without a history of trauma. Computer tomography demonstrated a fairly well defined extraconal lesion with opacification of the paranasal sinuses. The principal differential based on all findings was that of a spreading sinus infection and an extraconal tumor. An unprecedented finding of a spontaneous orbital hematoma was discovered when the patient was taken to theater. We discuss the rarity of this condition and its management.Keywords: hemorrhage, ophthalmology, spontaneous, intra-orbital, hematoma

  13. Spontaneous emphysema of the neck.

    Science.gov (United States)

    El-Ghazali, A M

    1983-04-01

    A case of spontaneous emphysema in the neck in a 17-year-old male was reported. Pathogenesis and management are discussed. Although it is a benign and self-limiting condition, it may carry a potential for serious complications.

  14. Spontaneous ischaemic stroke in dogs

    DEFF Research Database (Denmark)

    Gredal, Hanne Birgit; Skerritt, G. C.; Gideon, P.

    2013-01-01

    Translation of experimental stroke research into the clinical setting is often unsuccessful. Novel approaches are therefore desirable. As humans, pet dogs suffer from spontaneous ischaemic stroke and may hence offer new ways of studying genuine stroke injury mechanisms.......Translation of experimental stroke research into the clinical setting is often unsuccessful. Novel approaches are therefore desirable. As humans, pet dogs suffer from spontaneous ischaemic stroke and may hence offer new ways of studying genuine stroke injury mechanisms....

  15. First Industrial Tests of a Drum Monitor Matrix Correction for the Fissile Mass Measurement in Large Volume Historic Metallic Residues with the Differential Die-away Technique

    Energy Technology Data Exchange (ETDEWEB)

    Antoni, R.; Passard, C.; Perot, B.; Batifol, M.; Vandamme, J.C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 St Paul-lez-Durance, (France); Grassi, G. [AREVA NC, 1 place Jean-Millier, 92084 Paris-La-Defense cedex (France)

    2015-07-01

    The fissile mass in radioactive waste drums filled with compacted metallic residues (spent fuel hulls and nozzles) produced at AREVA La Hague reprocessing plant is measured by neutron interrogation with the Differential Die-away measurement Technique (DDT. In the next years, old hulls and nozzles mixed with Ion-Exchange Resins will be measured. The ion-exchange resins increase neutron moderation in the matrix, compared to the waste measured in the current process. In this context, the Nuclear Measurement Laboratory (NML) of CEA Cadarache has studied a matrix effect correction method, based on a drum monitor ({sup 3}He proportional counter inside the measurement cavity). A previous study performed with the NML R and D measurement cell PROMETHEE 6 has shown the feasibility of method, and the capability of MCNP simulations to correctly reproduce experimental data and to assess the performances of the proposed correction. A next step of the study has focused on the performance assessment of the method on the industrial station using numerical simulation. A correlation between the prompt calibration coefficient of the {sup 239}Pu signal and the drum monitor signal was established using the MCNPX computer code and a fractional factorial experimental design composed of matrix parameters representative of the variation range of historical waste. Calculations have showed that the method allows the assay of the fissile mass with an uncertainty within a factor of 2, while the matrix effect without correction ranges on 2 decades. In this paper, we present and discuss the first experimental tests on the industrial ACC measurement system. A calculation vs. experiment benchmark has been achieved by performing dedicated calibration measurement with a representative drum and {sup 235}U samples. The preliminary comparison between calculation and experiment shows a satisfactory agreement for the drum monitor. The final objective of this work is to confirm the reliability of the

  16. The Relationship among Spontaneity, Impulsivity, and Creativity

    Science.gov (United States)

    Kipper, David A.; Green, Doreen J.; Prorak, Amanda

    2010-01-01

    The present study was designed to investigate two characteristics of spontaneity, its relationship to creativity and to impulsivity. We hypothesized a positive relationship between spontaneity and creativity, consistent with Moreno, 1953 "canon of spontaneity-creativity." We also predicted a negative relationship between spontaneity and…

  17. Development of Counting Skills: Role of Spontaneous Focusing on Numerosity and Subitizing-Based Enumeration

    Science.gov (United States)

    Hannula, Minna M.; Rasanen, Pekka; Lehtinen, Erno

    2007-01-01

    Children differ in how much they spontaneously pay attention to quantitative aspects of their natural environment. We studied how this spontaneous tendency to focus on numerosity (SFON) is related to subitizing-based enumeration and verbal and object counting skills. In this exploratory study, children were tested individually at the age of 4-5…

  18. Spontaneous evaluative inferences and their relationship to spontaneous trait inferences.

    Science.gov (United States)

    Schneid, Erica D; Carlston, Donal E; Skowronski, John J

    2015-05-01

    Three experiments are reported that explore affectively based spontaneous evaluative impressions (SEIs) of stimulus persons. Experiments 1 and 2 used modified versions of the savings in relearning paradigm (Carlston & Skowronski, 1994) to confirm the occurrence of SEIs, indicating that they are equivalent whether participants are instructed to form trait impressions, evaluative impressions, or neither. These experiments also show that SEIs occur independently of explicit recall for the trait implications of the stimuli. Experiment 3 provides a single dissociation test to distinguish SEIs from spontaneous trait inferences (STIs), showing that disrupting cognitive processing interferes with a trait-based prediction task that presumably reflects STIs, but not with an affectively based social approach task that presumably reflects SEIs. Implications of these findings for the potential independence of spontaneous trait and evaluative inferences, as well as limitations and important steps for future study are discussed. (c) 2015 APA, all rights reserved).

  19. Optical antenna enhanced spontaneous emission.

    Science.gov (United States)

    Eggleston, Michael S; Messer, Kevin; Zhang, Liming; Yablonovitch, Eli; Wu, Ming C

    2015-02-10

    Atoms and molecules are too small to act as efficient antennas for their own emission wavelengths. By providing an external optical antenna, the balance can be shifted; spontaneous emission could become faster than stimulated emission, which is handicapped by practically achievable pump intensities. In our experiments, InGaAsP nanorods emitting at ∼ 200 THz optical frequency show a spontaneous emission intensity enhancement of 35 × corresponding to a spontaneous emission rate speedup ∼ 115 ×, for antenna gap spacing, d = 40 nm. Classical antenna theory predicts ∼ 2,500 × spontaneous emission speedup at d ∼ 10 nm, proportional to 1/d(2). Unfortunately, at d antenna efficiency drops below 50%, owing to optical spreading resistance, exacerbated by the anomalous skin effect (electron surface collisions). Quantum dipole oscillations in the emitter excited state produce an optical ac equivalent circuit current, I(o) = qω|x(o)|/d, feeding the antenna-enhanced spontaneous emission, where q|x(o)| is the dipole matrix element. Despite the quantum-mechanical origin of the drive current, antenna theory makes no reference to the Purcell effect nor to local density of states models. Moreover, plasmonic effects are minor at 200 THz, producing only a small shift of antenna resonance frequency.

  20. Spontaneous emission and absorber theory

    Science.gov (United States)

    Pegg, David T.

    1997-01-01

    One of the long term interests of George Series was the construction of a theory of spontaneous emission which does not involve field quantisation. His approach was written in terms of atomic operators only and he drew a parallel with the Wheeler-Feynman absorber theory of radiation. By making a particular extra postulate, he was able to obtain the correct spontaneous emission rate and the Lamb shift reasonably simply and directly. An examination of his approach indicates that this postulate is physically reasonable and the need for it arises because quantisation in his theory occurs after the response of the absorber has been accounted for by means of the radiative reaction field. We review briefly an alternative absorber theory approach to spontaneous emission based on the direct action between the emitting atom and a quantised absorber, and outline some applications to more recent effects of interest in quantum optics.

  1. Dynamics of spontaneous otoacoustic emissions

    Science.gov (United States)

    Bergevin, Christopher; Salerno, Anthony

    2015-12-01

    Spontaneous otoacoustic emissions (SOAEs) have become a hallmark feature in modern theories of an `active' inner ear, given their numerous correlations to auditory function (e.g., threshold microstructure, neurophysiological tuning curves), near universality across tetrapod classes, and physiological correlates at the single hair cell level. However, while several different classes of nonlinear models exist that describe the mechanisms underlying SOAE generation (e.g., coupled limit-cycle oscillators, global standing waves), there is still disagreement as to precisely which biophysical concepts are at work. Such is further compounded by the idiosyncratic nature of SOAEs: Not all ears emit, and when present, SOAE activity can occur at seemingly arbitrary frequencies (though always within the most sensitive range of the audiogram) and in several forms (e.g., peaks, broad `baseline' plateaus). The goal of the present study was to develop new signal processing and stimulation techniques that would allow for novel features of SOAE activity to be revealed. To this end, we analyzed data from a variety of different species: human, lizard, and owl. First, we explored several strategies for examining SOAE waveforms in the absence of external stimuli to further ascertain what constitutes `self-sustained sinusoids' versus `filtered noise'. We found that seemingly similar peaks in the spectral domain could exhibit key differences in the time domain, which we interpret as providing critical information about the underlying oscillators and their coupling. Second, we introduced dynamic stimuli (swept-tones, tone bursts) at a range of levels, whose interaction with SOAEs could be visualized in the time-frequency domain. Aside from offering a readily accessible way to visualize many previously reported effects (e.g., entrainment, facilitation), we observed several new features such as subharmonic distortion generation and competing pulling/pushing effects when multiple tones were

  2. Pseudoarachnoiditis in Spontaneous Intracranial Hypotension

    Directory of Open Access Journals (Sweden)

    Özlem Alkan

    2011-03-01

    Full Text Available Spontaneous intracranial hypotension is an important cause of new daily persistent headaches in young and middle-aged individuals. The diagnosis is made based on low cerebrospinal fluid pressure with characteristic findings upon brain and spinal magnetic resonance imaging (MRI. We present the case of a 15-year-old boy with spontaneous intracranial hypotension. Although his brain MRI was normal, his lumbar spinal MRI showed clustering of the nerve roots characteristic of arachnoiditis. Radionuclide cisternography revealed an epidural leak, which was treated with an epidural blood patch. The patient reached a near-full recovery within 24 h, and the lumbar spinal MRI findings mimicking arachnoiditis disappeared.

  3. Spontaneous isolated celiac artery dissection

    Directory of Open Access Journals (Sweden)

    Tuba Cimilli Ozturk

    2011-01-01

    Full Text Available Dyspepsia with mild, stabbing epigastric discomfort without history of trauma is a very common symptom that emergency physicians see in their daily practice. Vascular emergencies, mostly the aortic dissection and aneurysm, are always described in the differential diagnosis with persistent symptoms. Isolated celiac artery dissection occurring spontaneously is a very rare diagnosis. The involvement of branch vessels is generally observed and patients show various clinical signs and symptoms according to the involved branch vessel. Here we are presenting a case with spontaneous isolated celiac artery dissection, without any branch vessel involvement or visceral damage, detected by computed tomography scans taken on admission.

  4. Spontaneous rupture of vaginal enterocele

    DEFF Research Database (Denmark)

    Svendsen, Jesper Hastrup; Galatius, H; Hansen, P K

    1985-01-01

    Spontaneous rupture of an enterocele is a rare complication. Only 24 cases including the present case have been reported in the literature. The patients were elderly and had had at least one vaginal operation. The patients were remarkably unaffected symptomatically on admission.......Spontaneous rupture of an enterocele is a rare complication. Only 24 cases including the present case have been reported in the literature. The patients were elderly and had had at least one vaginal operation. The patients were remarkably unaffected symptomatically on admission....

  5. Spontaneous rupture of vaginal enterocele

    DEFF Research Database (Denmark)

    Svendsen, Jesper Hastrup; Galatius, H; Hansen, P K

    1985-01-01

    Spontaneous rupture of an enterocele is a rare complication. Only 24 cases including the present case have been reported in the literature. The patients were elderly and had had at least one vaginal operation. The patients were remarkably unaffected symptomatically on admission.......Spontaneous rupture of an enterocele is a rare complication. Only 24 cases including the present case have been reported in the literature. The patients were elderly and had had at least one vaginal operation. The patients were remarkably unaffected symptomatically on admission....

  6. Spontaneous waves in muscle fibres

    Science.gov (United States)

    Günther, Stefan; Kruse, Karsten

    2007-11-01

    Mechanical oscillations are important for many cellular processes, e.g. the beating of cilia and flagella or the sensation of sound by hair cells. These dynamic states originate from spontaneous oscillations of molecular motors. A particularly clear example of such oscillations has been observed in muscle fibers under non-physiological conditions. In that case, motor oscillations lead to contraction waves along the fiber. By a macroscopic analysis of muscle fiber dynamics we find that the spontaneous waves involve non-hydrodynamic modes. A simple microscopic model of sarcomere dynamics highlights mechanical aspects of the motor dynamics and fits with the experimental observations.

  7. Chemical pleurodesis for spontaneous pneumothorax.

    Science.gov (United States)

    How, Cheng-Hung; Hsu, Hsao-Hsun; Chen, Jin-Shing

    2013-12-01

    Pneumothorax is defined as the presence of air in the pleural cavity. Spontaneous pneumothorax, occurring without antecedent traumatic or iatrogenic cause, is sub-divided into primary and secondary. The severity of pneumothorax could be varied from asymptomatic to hemodynamically compromised. Optimal management of this benign disease has been a matter of debate. In addition to evacuating air from the pleural space by simple aspiration or chest tube drainage, the management of spontaneous pneumothorax also focused on ceasing air leakage and preventing recurrences by surgical intervention or chemical pleurodesis. Chemical pleurodesis is a procedure to achieve symphysis between the two layers of pleura by sclerosing agents. In the current practice guidelines, chemical pleurodesis is reserved for patients unable or unwilling to receive surgery. Recent researches have found that chemical pleurodesis is also safe and effective in preventing pneumothorax recurrence in patients with the first episode of spontaneous pneumothorax or after thoracoscopic surgery and treating persistent air leakage after thoracoscopic surgery. In this article we aimed at exploring the role of chemical pleurodesis for spontaneous pneumothorax, including ceasing air leakage and preventing recurrence. The indications, choice of sclerosants, safety, effects, and possible side effects or complications of chemical pleurodesis are also reviewed here.

  8. Silicosis with bilateral spontaneous pneumothorax

    Directory of Open Access Journals (Sweden)

    Fotedar Sanjay

    2010-01-01

    Full Text Available Presentation with simultaneous bilateral pneumothorax is uncommon and usually in the context of secondary spontaneous pneumothorax.The association of pneumothorax and silicosis is infrequent and most cases are unilateral. Bilateral pneumothorax in silicosis is very rare with just a few reports in medical literature.

  9. Shell theorem for spontaneous emission

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Mortensen, Jakob Egeberg; Lodahl, Peter;

    2013-01-01

    and therefore is given exactly by the dipole approximation theory. This surprising result is a spontaneous emission counterpart to the shell theorems of classical mechanics and electrostatics and provides insights into the physics of mesoscopic emitters as well as great simplifications in practical calculations....

  10. Spontaneous resolution of subfoveal perfluorocarbon

    Directory of Open Access Journals (Sweden)

    Oellers P

    2015-03-01

    Full Text Available Patrick Oellers,1 Leon D Charkoudian,2 Paul Hahn11Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA; 2Cape Fear Retinal Associates, Wilmington, NC, USA Abstract: Perfluorocarbon liquids (PFCL have transformed the surgical approach to complex retinal detachments, but their use can be complicated by subretinal retention. Migration of peripherally located subretinal PFCL towards the fovea is well established, but spontaneous resolution of subfoveal PFCL without surgical evacuation or displacement has rarely been described. We present a case of a large single retained subfoveal PFCL droplet following vitrectomy with membrane peeling, inferior relaxing retinectomy, and silicone oil tamponade that demonstrated spontaneous resolution 3 weeks postoperatively, with subsequent anatomic and visual improvement. No residual subretinal PFCL was noted, and we hypothesize that the PFCL droplet spontaneously extruded through a transient hole created in the thinned retina overlying the droplet, which subsequently closed spontaneously. Further understanding of the mechanisms of PFCL migration and resolution may facilitate improved treatments for this complication.Keywords: perfluorocarbon, subretinal, retained, resolution

  11. Spontaneous bilateral quadriceps tendon rupture.

    Science.gov (United States)

    Vigneswaran, N; Lee, K; Yegappan, M

    2007-11-01

    Spontaneous bilateral quadriceps tendon ruptures are uncommon. We present a 30-year-old man with end-stage renal failure, who sustained this injury, and subsequently had surgical repair of both tendons on separate occasions. He has since regained full range of movement of both knees.

  12. Biomarkers of spontaneous preterm birth

    DEFF Research Database (Denmark)

    Polettini, Jossimara; Cobo, Teresa; Kacerovsky, Marian

    2017-01-01

    Despite decades of research on risk indicators of spontaneous preterm birth (PTB), reliable biomarkers are still not available to screen or diagnose high-risk pregnancies. Several biomarkers in maternal and fetal compartments have been mechanistically linked to PTB, but none of them are reliable...

  13. Student Experiments in Spontaneous Fission.

    Science.gov (United States)

    Becchetti, F. D.; Ying, J. S.

    1981-01-01

    Advanced undergraduate experiments utilizing a commercially available, thin spontaneous fission source are described, including studies of the energy and mass distribution of the fission fragments and their energy and angular correlation. The experiments provide a useful introduction to fission, nuclear mass equations, heavy-ion physics, and…

  14. Prediction of Spontaneous Preterm Birth

    NARCIS (Netherlands)

    Dijkstra, Karolien

    2002-01-01

    Preterm birth is a leading cause of neonatal morbidity and mortality. It is a major goal in obstetrics to lower the incidence of spontaneous preterm birth (SPB) and related neonatal morbidity and mortality. One of the principal objectives is to discover early markers that would allow us to identify

  15. Prediction of Spontaneous Preterm Birth

    NARCIS (Netherlands)

    Dijkstra, Karolien

    2002-01-01

    Preterm birth is a leading cause of neonatal morbidity and mortality. It is a major goal in obstetrics to lower the incidence of spontaneous preterm birth (SPB) and related neonatal morbidity and mortality. One of the principal objectives is to discover early markers that would allow us to identify

  16. Measurement of the neutron capture cross section of the fissile isotope $^{235}$U with the CERN n_TOF Total Absorption Calorimeter and a fission tagging based on micromegas detectors

    CERN Document Server

    Mendoza, E; Cano-Ott, D; Guerrero, C; Berthoumieux, E; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Becvár, F; Belloni, F; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Gunsing, F; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Kawano, T; Kivel, N; Koehler, P; Kokkoris, M; Korschinek, G; Krticka, M; Kroll, J; Langer, C; Lampoudis, C; Leal-Cidoncha, E; Lederer, C; Leeb, H; Leong, L S; Losito, R; Manousos, A; Marganiec, J; Martínez, T; Mastinu, P F; Mastromarco, M; Massimi, C; Meaze, M; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondelaers, W; Paradela, C; Pavlik, A; Perkowski, J; Pignatari, M; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Schumann, D; Stetcu, I; Sabaté, M; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiss, C; Wright, T; Zugec, P

    2014-01-01

    Actual and future nuclear technologies require more accurate nuclear data on the (n, $\\gamma$) cross sections and $\\alpha$-ratios of fissile isotopes. Their measurement presents several difficulties, mainly related to the strong fission $\\gamma$-ray background competing with the weaker $\\gamma$-ray cascades used as the experimental signature of the (n, $\\gamma$) process. A specific setup has been used at the CERN n_TOF facility in 2012 for the measurement of the (n,$\\gamma$ ) cross section and $\\alpha$- ratios of fissile isotopes and used for the case of the $^{235}$U isotope. The setup consists in a set of micromegas fission detectors surrounding $^{235}$U samples and placed inside the segmented BaF$_2$ Total Absorption Calorimeter.

  17. Measurement of the Neutron Capture Cross Section of the Fissile Isotope 235U with the CERN n_TOF Total Absorption Calorimeter and a Fission Tagging Based on Micromegas Detectors

    CERN Document Server

    Balibrea, J; Cano-Ott, D; Guerrero, C; Berthoumieux, E; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Gunsing, F; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Kawano, T; Kivel, N; Koehler, P; Kokkoris, M; Korschinek, G; Krtička, M; Kroll, J; Langer, C; Lampoudis, C; Lederer, C; Leeb, H; Leong, L S; Losito, R; Manousos, A; Marganiec, J; Martínez, T; Mastinu, P F; Mastromarco, M; Massimi, C; Meaze, M; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondelaers, W; Paradela, C; Pavlik, A; Perkowski, J; Pignatari, M; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Schumann, D; Stetcu, I; Sabaté, M; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T J; Žugec, P

    Current and future nuclear technologies require more accurate nuclear data on (n,γ) cross sections and the α-ratios of fissile isotopes. Their measurement presents several difficulties, mainly related to the strong fission γ-ray background competing with the weaker γ-ray cascades used as the experimental signature of the (n,γ) process. A specific setup was used at the CERN n_TOF facility in 2012 for the measurement of the (n,γ) cross section and α-ratios of fissile isotopes and used for the case of the 235U isotope. The setup consists of a set of micromegas fission detectors surrounding the 235U samples all placed inside a segmented BaF2 Total Absorption Calorimeter.

  18. A Case of Spontaneously Resolved Bilateral Primary Spontaneous Pneumothorax

    Directory of Open Access Journals (Sweden)

    Hasan Kahraman

    2014-03-01

    Full Text Available A condition of intrapleural air-space accumulation in individuals without any history of trauma or lung disease is called as primary spontaneous pneumothorax (PSP. Sixteen-years-old male patient admitted with complains of chest pain and dyspnea beginning 3 day ago. On physical examination, severity of breath sounds decreased on right side. Chest radiograph was taken and right-sided pneumothorax was detected and tube thoracostomy was inserted. Two months ago the patient referred to a doctor with similar complaints and physical examination and chest radiograph were reported as normal. The radiograph was retrospectively examined and bilateral PSP was detected. We presented the case duo to spontaneous recovery of bilateral PSP is seen very rarely and so contributes data to the literature. In patients admitted to the clinic with chest pain and shortness of breath, pneumothorax should be considered at differential diagnosis.

  19. Constrained gauge fields from spontaneous Lorentz violation

    DEFF Research Database (Denmark)

    Chkareuli, J. L.; Froggatt, C. D.; Jejelava, J. G.

    2008-01-01

    Spontaneous Lorentz violation realized through a nonlinear vector field constraint of the type AµAµ=M2 (M is the proposed scale for Lorentz violation) is shown to generate massless vector Goldstone bosons, gauging the starting global internal symmetries in arbitrary relativistically invariant...... theories. The gauge invariance appears in essence as a necessary condition for these bosons not to be superfluously restricted in degrees of freedom, apart from the constraint due to which the true vacuum in a theory is chosen by the Lorentz violation. In the Abelian symmetry case the only possible theory...... proves to be QED with a massless vector Goldstone boson naturally associated with the photon, while the non-Abelian symmetry case results in a conventional Yang-Mills theory. These theories, both Abelian and non-Abelian, look essentially nonlinear and contain particular Lorentz (and CPT) violating...

  20. Spontaneous Heterotopic Triplet Pregnancy With Tubal Rupture

    Directory of Open Access Journals (Sweden)

    Lima Arsala MBBS, BBMedSci

    2014-04-01

    Full Text Available The recent increase in heterotopic pregnancies has been largely attributed to the increased use of assisted reproduction technologies. We report the rare case of a multiparous woman with a spontaneous conception resulting in a triplet heterotopic pregnancy: a twin intrauterine pregnancy and a single right tubal ectopic pregnancy. Heterotopic pregnancy is a rare and potentially life-threatening condition in which simultaneous gestations occur at 2 or more implantation sites. It is infrequent in natural conception cycles, occurring in 1:30 000 pregnancies. However, the prevalence is rising with the increased use of assisted reproduction techniques to that of 1:100 to 1:500 in these patient subgroups, highlighting the need to incorporate it into a clinician’s diagnostic algorithm.

  1. Muon Tomography Algorithms for Fissile Nuclear Materials Detection%宇宙射线μ子探测裂变核材料的成像算法

    Institute of Scientific and Technical Information of China (English)

    王烈铭; 王红艳; 刘志英; 杨宏伟; 庞洪超

    2011-01-01

    宇宙射线μ子探测作为一种清洁源、深穿透、真正识别裂变核材料的新方法正在世界范围内日益受到重视,我国也在反恐领域开展此项研究,论文介绍了研究工作中图像重建算法(PoCA算法、期望最大化算法)以及算法模拟实验结果和分析,模拟结果初步证明了宇宙线μ子进行特殊核材料检测的可行性以及图像重建算法的有效性.%Muon Tomography is a novel technique which exploits the multiple coulomb scattering of these particles for nondestructive inspection without the use of artificial radiation. It describes the concept and theory of cosmic - ray muon tomography, and discuss preliminary and advanced reconstruction algorithms ( PoCA algorithm and MLS - EM algorithm) .which take advantage of the scattering angle. Our algorithms are validated with simulation experimental demonstrations. Based upon the results from simulations, we conclude that muon radiography can be useful for detecting fissile nuclear materials.

  2. Spontaneous internal carotid artery dissection.

    Science.gov (United States)

    Khimenko, L P; Esham, H R; Ahmed, W

    2000-10-01

    Once considered uncommon, spontaneous dissection of the carotid artery is an increasingly recognized cause of stroke, headache, cranial nerve palsy, or ophthalmologic events, especially in young adults. Even in the presence of existing signs and symptoms, the diagnosis can be missed by experienced physicians of all specialties. We report a case of spontaneous internal carotid artery dissection in a 38-year-old woman with a cortical stroke and visual disturbances as initial symptoms. The diagnosis was confirmed by magnetic resonance imaging/angiography and by angiography. Prompt anticoagulation was instituted, and the patient had complete resolution of symptoms. Cervicocephalic arterial dissection should be included in the differential diagnosis of the causes of cerebrovascular events.

  3. Spontaneous Photon Emission in Cavities

    Directory of Open Access Journals (Sweden)

    Alber G.

    2014-01-01

    Full Text Available We investigate spontaneous photon emission processes of two-level atoms in parabolic and ellipsoidal cavities thereby taking into account the full multimode scenario. In particular, we calculate the excitation probabilities of the atoms and the energy density of the resulting few-photon electromagnetic radiation field by using semiclassical methods for the description of the multimode scenario. Based on this approach photon path representations are developed for relevant transition probability amplitudes which are valid in the optical frequency regime where the dipole and the rotating-wave approximations apply. Comparisons with numerical results demonstrate the quality of these semiclassical results even in cases in which the wave length of a spontaneously emitted photon becomes comparable or even larger than characteristic length scales of the cavity. This is the dynamical regime in which diffraction effects become important so that geometric optical considerations are typically not applicable.

  4. Spontaneous Rotational Inversion in Phycomyces

    KAUST Repository

    Goriely, Alain

    2011-03-01

    The filamentary fungus Phycomyces blakesleeanus undergoes a series of remarkable transitions during aerial growth. During what is known as the stagea IV growth phase, the fungus extends while rotating in a counterclockwise manner when viewed from above (stagea IVa) and then, while continuing to grow, spontaneously reverses to a clockwise rotation (stagea IVb). This phase lasts for 24-48Ah and is sometimes followed by yet another reversal (stageAIVc) before the overall growth ends. Here, we propose a continuum mechanical model of this entire process using nonlinear, anisotropic, elasticity and show how helical anisotropy associated with the cell wall structure can induce spontaneous rotation and, under appropriate circumstances, the observed reversal of rotational handedness. © 2011 American Physical Society.

  5. Spontaneous resolution of subfoveal perfluorocarbon

    OpenAIRE

    Oellers P; Charkoudian LD; Hahn P

    2015-01-01

    Patrick Oellers,1 Leon D Charkoudian,2 Paul Hahn11Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA; 2Cape Fear Retinal Associates, Wilmington, NC, USA Abstract: Perfluorocarbon liquids (PFCL) have transformed the surgical approach to complex retinal detachments, but their use can be complicated by subretinal retention. Migration of peripherally located subretinal PFCL towards the fovea is well established, but spontaneous resolution of subfoveal PFCL witho...

  6. CSIR helps prevent spontaneous combustion

    Energy Technology Data Exchange (ETDEWEB)

    Vuuren, M. van (CSIR Energy Technology (South Africa))

    1992-03-01

    Heaps of stockpiled coal could present a fire hazard due to the risk of spontaneous combustion. Regular monitoring of stockpiles and bunker testing of coals help to prevent stockpile fires. This brief article describes the recent upgrading of the CSIR's bunker test facility that enables coal producers, users and exporters to test their products under simulated conditions that duplicate the actual conditions under which coal is stored. 2 photos.

  7. Spontaneous Perforation of Rectosigmoid Colon

    Directory of Open Access Journals (Sweden)

    Farhad Haj Sheikholeslami

    2010-12-01

    Full Text Available Spontaneous perforation of the sigmoid colon or rectom is definedas a sudden perforation of the colon in the absence of diseasessuch as tumors, diverticulosis or external injury. It is avery rare finding, and if neglected, results in severe peritonitisand high mortality. The causes of this rare condition are numerous,and in this case it might be due to the chronic constipationinduced by an anticholinergic antipsychotic.Iran J Med Sci 2010; 35(4: 339-341.

  8. Spontaneous Splenic Rupture in Melanoma

    Directory of Open Access Journals (Sweden)

    Hadi Mirfazaelian

    2014-01-01

    Full Text Available Spontaneous rupture of spleen due to malignant melanoma is a rare situation, with only a few case reports in the literature. This study reports a previously healthy, 30-year-old man who came with chief complaint of acute abdominal pain to emergency room. On physical examination, abdominal tenderness and guarding were detected to be coincident with hypotension. Ultrasonography revealed mild splenomegaly with moderate free fluid in abdominopelvic cavity. Considering acute abdominal pain and hemodynamic instability, he underwent splenectomy with splenic rupture as the source of bleeding. Histologic examination showed diffuse infiltration by tumor. Immunohistochemical study (positive for S100, HMB45, and vimentin and negative for CK, CD10, CK20, CK7, CD30, LCA, EMA, and chromogranin confirmed metastatic malignant melanoma. On further questioning, there was a past history of a nasal dark skin lesion which was removed two years ago with no pathologic examination. Spontaneous (nontraumatic rupture of spleen is an uncommon situation and it happens very rarely due to neoplastic metastasis. Metastasis of malignant melanoma is one of the rare causes of the spontaneous rupture of spleen.

  9. Atomic nuclei decay modes by spontaneous emission of heavy ions

    OpenAIRE

    Poenaru, Dorin N.; Ivaşcu, Marin; Săndulescu, Aurel; Greiner, Walter

    2006-01-01

    The great majority of the known nuclides with Z>40, including the so-called stable nuclides, are metastable with respect to several modes of spontaneous superasymmetric splitting. A model extended from the fission theory of alpha decay allows one to estimate the lifetimes and the branching ratios relative to the alpha decay for these natural radioactivities. From a huge amount of systematic calculations it is concluded that the process should proceed with maximum intensity in the trans-lead n...

  10. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    R A Gherghescu; D N Poenaru

    2015-09-01

    The macroscopic–microscopic method is extended to calculate the deformation energy and penetrability for binary nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped daughter and emitted fragment nuclei. The macroscopic part is obtained using the Yukawa-plus-exponential potential. The microscopic shell and pairing corrections are obtained using the Strutinsky and BCS approaches and the cranking formulae yield the inertia tensor. Finally, the WKB method is used to calculate penetrabilities and spontaneous fission half-lives. Calculations are performed for the decay of 282,292120 nuclei.

  11. Spontaneous osteonecrosis of the knee

    Energy Technology Data Exchange (ETDEWEB)

    Kattapuram, Taj M. [Department of Radiology, Massachusetts General Hospital (United States); Kattapuram, Susan V. [Department of Radiology, Massachusetts General Hospital (United States)], E-mail: skattapuram@partners.org

    2008-07-15

    Spontaneous osteonecrosis of the knee presents with acute onset of severe, pain in elderly patients, usually female and usually without a history of trauma. Originally described as idiopathic osteonecrosis, the exact etiology is still debated. Evidence suggests that an acute fracture occurs as a result of chronic stress or minor trauma to a weakened subchondral bone plate. The imaging characteristics on MR reflect the age of the lesion and the symptoms. More appropriate terminology may be ' subchondral insufficiency fracture of the knee' or 'focal subchondral osteonecrosis'.

  12. Spontaneous emission of heavy clusters

    Energy Technology Data Exchange (ETDEWEB)

    Poenaru, D.N.; Ivascu, M. (Central Inst. of Physics, Bucharest (Romania)); Sandulescu, A. (Joint Inst. for Nuclear Research, Dubna (USSR)); Greiner, W. (Frankfurt Univ. (Germany, F.R.))

    1984-08-01

    The lifetimes of some heavy nuclei relative to the spontaneous emission of various clusters heavier than the alpha particle are estimated with a model extended from the fission theory of alpha decay, showing that this phenomenon is a new manifestation of the nuclear shell structure. A greater probability is obtained for parent-heavy-cluster combinations leading to a magic or almost magic daughter nucleus. The analytical formula obtained allows the handling of a large number of cases to search for new kinds of radioactivities.

  13. Driving factors of the communities of phytophagous and predatory mites in a physic nut plantation and spontaneous plants associated.

    Science.gov (United States)

    Cruz, Wilton P; Sarmento, Renato A; Teodoro, Adenir V; Neto, Marçal P; Ignacio, Maíra

    2013-08-01

    Seasonal changes in climate and plant diversity are known to affect the population dynamics of both pests and natural enemies within agroecosystems. In Brazil, spontaneous plants are usually tolerated in small-scale physic nut plantations over the year, which in turn may mediate interactions between pests and natural enemies within this agroecosystem. Here, we aimed to access the influence of seasonal variation of abiotic (temperature, relative humidity and rainfall) and biotic (diversity of spontaneous plants, overall richness and density of mites) factors on the communities of phytophagous and predatory mites found in a physic nut plantation and its associated spontaneous plants. Mite sampling was monthly conducted in dicotyledonous and monocotyledonous leaves of spontaneous plants as well as in physic nut shrubs over an entire year. In the dry season there was a higher abundance of phytophagous mites (Tenuipalpidae, Tarsonemidae and Tetranychidae) on spontaneous plants than on physic nut shrubs, while predatory mites (Phytoseiidae) showed the opposite pattern. The overall density of mites on spontaneous plants increased with relative humidity and diversity of spontaneous plants. Rainfall was the variable that most influenced the density of mites inhabiting physic nut shrubs. Agroecosystems comprising spontaneous plants associated with crops harbour a rich mite community including species of different trophic levels which potentially benefit natural pest control due to increased diversity and abundance of natural enemies.

  14. Fast random number generation with spontaneous emission noise of a single-mode semiconductor laser

    Science.gov (United States)

    Zhang, Jianzhong; Zhang, Mingjiang; Liu, Yi; Li, Pu; Yi, Xiaogang; Zhang, Mingtao; Wang, Yuncai

    2016-11-01

    We experimentally demonstrate a 12.5 Gb s-1 random number generator based on measuring the spontaneous emission noise of a single-mode semiconductor laser. The spontaneous emission of light is quantum mechanical in nature and is an inborn physical entropy source of true randomness. By combining a high-speed analog-to-digital converter and off-line processing, random numbers are extracted from the spontaneous emission with the verified randomness. The generator is simple, robust, and with no need of accurately tuning the comparison threshold. The use of semiconductor lasers makes it particularly compatible with the delivery of random numbers in optical networks.

  15. Spontaneous biliary peritonitis in children.

    Science.gov (United States)

    Kohli, Supreethi; Singhal, Anu; Arora, Anita; Singhal, Sanjeev

    2013-01-01

    Pediatric Spontaneous Bile duct perforation is a rare clinical condition with only around 150 cases reported worldwide. Early management gives excellent prognosis but the condition often presents a diagnostic dilemma. Hepato-biliary Technetium-99m-iminodiacetic acid scintiscan is the diagnostic investigation of choice but its availability in third world countries is limited. We present two cases of spontaneous biliary peritonitis in children, which were diagnosed without scintiscanning. The first case was a one-and -a half-year-old child, who was diagnosed with biliary peritonitis without pneumoperitoneum by a combination of Ultrasound (USG), Contrast enhanced computed tomography (CECT), and Magnetic Resonance Imaging (MRI). The child underwent USG-guided drainage and subsequent cholecystectomy with hepatico-jejunostomy. The second child also had biliary peritonitis without pneumoperitoneum, which was initially suspected on USG. CECT revealed dilated gall bladder and fluid collection in sub-hepatic space and pelvis. Abdominal paracentesis revealed presence of bile. The child responded to conservative therapy. Both are doing well on two-year follow-up. In a patient with jaundice, biliary tract abnormalities and/or free fluid, either generalized or localized to peri-cholecystic/sub-hepatic space on USG/CT/MRI, in the absence of pneumoperitoneum, suggest a diagnosis of biliary perforation even in the absence of scintiscanning.

  16. Spontaneous Biliary Peritonitis in Children

    Directory of Open Access Journals (Sweden)

    Supreethi Kohli

    2013-01-01

    Full Text Available Pediatric Spontaneous Bile duct perforation is a rare clinical condition with only around 150 cases reported worldwide. Early management gives excellent prognosis but the condition often presents a diagnostic dilemma. Hepato-biliary Technetium-99m-iminodiacetic acid scintiscan is the diagnostic investigation of choice but its availability in third world countries is limited. We present two cases of spontaneous biliary peritonitis in children, which were diagnosed without scintiscanning. The first case was a one-and -a half-year-old child, who was diagnosed with biliary peritonitis without pneumoperitoneum by a combination of Ultrasound (USG, Contrast enhanced computed tomography (CECT, and Magnetic Resonance Imaging (MRI. The child underwent USG-guided drainage and subsequent cholecystectomy with hepatico-jejunostomy. The second child also had biliary peritonitis without pneumoperitoneum, which was initially suspected on USG. CECT revealed dilated gall bladder and fluid collection in sub-hepatic space and pelvis. Abdominal paracentesis revealed presence of bile. The child responded to conservative therapy. Both are doing well on two-year follow-up. In a patient with jaundice, biliary tract abnormalities and/or free fluid, either generalized or localized to peri-cholecystic/sub-hepatic space on USG/CT/MRI, in the absence of pneumoperitoneum, suggest a diagnosis of biliary perforation even in the absence of scintiscanning.

  17. Spontaneous recovery in dynamical networks

    Science.gov (United States)

    Majdandzic, Antonio; Podobnik, Boris; Buldyrev, Sergey V.; Kenett, Dror Y.; Havlin, Shlomo; Eugene Stanley, H.

    2014-01-01

    Much research has been carried out to explore the structural properties and vulnerability of complex networks. Of particular interest are abrupt dynamic events that cause networks to irreversibly fail. However, in many real-world phenomena, such as brain seizures in neuroscience or sudden market crashes in finance, after an inactive period of time a significant part of the damaged network is capable of spontaneously becoming active again. The process often occurs repeatedly. To model this marked network recovery, we examine the effect of local node recoveries and stochastic contiguous spreading, and find that they can lead to the spontaneous emergence of macroscopic `phase-flipping' phenomena. As the network is of finite size and is stochastic, the fraction of active nodes z switches back and forth between the two network collective modes characterized by high network activity and low network activity. Furthermore, the system exhibits a strong hysteresis behaviour analogous to phase transitions near a critical point. We present real-world network data exhibiting phase switching behaviour in accord with the predictions of the model.

  18. Spontaneous Hybridization between Pinus mugo and Pinus sylvestris at the Lithuanian Seaside: A Morphological Survey

    OpenAIRE

    Darius Danusevičius; Vitas Marozas; Gediminas Brazaitis; Raimundas Petrokas; Knud Ib Christensen

    2012-01-01

    We address the problem of spontaneous hybridization between an exotic species Pinus mugo and the native/local P. sylvestris at the seaside spit of Kursiu Nerija in Lithuania. The objective was to identify spontaneous hybrids between P. mugo and P. sylvestris based on morphology traits among the individuals naturally regenerating at the seaside spit. The field inventory was carried out over the entire Lithuanian part of the spit, and 200 individuals morphologically intermediate between P. sylv...

  19. Diversity and the role of yeast in spontaneous cocoa bean fermentation from Southeast Sulawesi, Indonesia

    OpenAIRE

    JAMILI; NUR ARFA YANTI; PRIMA ENDANG SUSILOWATI

    2016-01-01

    Abstract. Jamili, Yanti NA, Susilowati PE. 2016. Diversity and the role of yeast in spontaneous cocoa bean fermentation from Southeast Sulawesi, Indonesia. Biodiversitas 17: 90-95. Yeast is one of the microbial group which is role in the process of cocoa spontaneously fermentation. The objective of this study was to determinate and to know the diversity of yeast that role on cocoa bean fermentation. Yeast was isolated by pour plate method from cocoa bean that was naturally fermented by a coco...

  20. A Case of Multiple Spontaneous Keloid Scars

    Directory of Open Access Journals (Sweden)

    Abdulhadi Jfri

    2015-07-01

    Full Text Available Keloid scars result from an abnormal healing response to cutaneous injury or inflammation that extends beyond the borders of the original wound. Spontaneous keloid scars forming in the absence of any previous trauma or surgical procedure are rare. Certain syndromes have been associated with this phenomenon, and few reports have discussed the evidence of single spontaneous keloid scar, which raises the question whether they are really spontaneous. Here, we present a 27-year-old mentally retarded single female with orbital hypertelorism, broad nasal bridge, repaired cleft lip and high-arched palate who presented with progressive multiple spontaneous keloid scars in different parts of her body which were confirmed histologically by the presence of typical keloidal collagen. This report supports the fact that keloid scars can appear spontaneously and are possibly linked to a genetic factor. Furthermore, it describes a new presentation of spontaneous keloid scars in the form of multiple large lesions in different sites of the body.

  1. Basic theory research of coal spontaneous combustion

    Institute of Scientific and Technical Information of China (English)

    WANG Ji-ren; SUN Yan-qiu; ZHAO Qing-fu; DENG Cun-bao; DENG Han-zhong

    2008-01-01

    Discussed latest research results of basic theory research of coal spontaneous combustion in detail, with quantum chemical theory and method and experiment systematically studied chemical structure of coal molecule, adsorption mechanism of coal surface to oxygen molecule and chemical reaction mechanism and process of spontaneous combustion of organic macromolecule and low molecular weight compound in coal from microcosmic view, and established complete theoretical system of the mechanism of coal spontaneous combustion.

  2. Association between Nutritional Status with Spontaneous Abortion

    OpenAIRE

    Ahmadi, Rahimeh; Ziaei, Saeideh; Parsay, Sosan

    2016-01-01

    Background Spontaneous abortion is the most common adverse pregnancy outcome. We aimed to investigate a possible link between nutrient deficiencies and the risk of spontaneous abortion. Materials and Methods This case-control study included the case group (n=331) experiencing a spontaneous abortion before 14 weeks of pregnancy and the control group (n=331) who were healthy pregnant women over 14 weeks of pregnancy. The participants filled out Food Frequency Questionnaire (FFQ), in which they ...

  3. Association between Nutritional Status with Spontaneous Abortion

    OpenAIRE

    Rahimeh Ahmadi; Saeideh Ziaei; Sosan Parsay

    2016-01-01

    Background: Spontaneous abortion is the most common adverse pregnancy outcome. We aimed to investigate a possible link between nutrient deficiencies and the risk of spontaneous abortion. Materials and Methods: This case-control study included the case group (n=331) experiencing a spontaneous abortion before 14 weeks of pregnancy and the control group (n=331) who were healthy pregnant women over 14 weeks of pregnancy. The participants filled out Food Frequency Questionnaire (...

  4. SPONTANEOUS COAL COMBUSTION; MECHANISMS AND PREDICTION.

    Science.gov (United States)

    Herring, James R.; Rich, Fredrick J.

    1983-01-01

    Spontaneous ignition and combustion of coal is a major problem to the coal mining, shipping, and use industries; unintentional combustion causes loss of the resource as well as jeopardy to life and property. The hazard to life is especially acute in the case of underground coal mine fires that start by spontaneous ignition. It is the intention of this research to examine previously suggested causes of spontaneous ignition, to consider new evidence, and to suggest an experimental approach to determine which of these suggested causes is relevant to western U. S. coal. This discussion focuses only on causes and mechanism of spontaneous ignition.

  5. Learning shapes spontaneous activity itinerating over memorized states.

    Directory of Open Access Journals (Sweden)

    Tomoki Kurikawa

    Full Text Available Learning is a process that helps create neural dynamical systems so that an appropriate output pattern is generated for a given input. Often, such a memory is considered to be included in one of the attractors in neural dynamical systems, depending on the initial neural state specified by an input. Neither neural activities observed in the absence of inputs nor changes caused in the neural activity when an input is provided were studied extensively in the past. However, recent experimental studies have reported existence of structured spontaneous neural activity and its changes when an input is provided. With this background, we propose that memory recall occurs when the spontaneous neural activity changes to an appropriate output activity upon the application of an input, and this phenomenon is known as bifurcation in the dynamical systems theory. We introduce a reinforcement-learning-based layered neural network model with two synaptic time scales; in this network, I/O relations are successively memorized when the difference between the time scales is appropriate. After the learning process is complete, the neural dynamics are shaped so that it changes appropriately with each input. As the number of memorized patterns is increased, the generated spontaneous neural activity after learning shows itineration over the previously learned output patterns. This theoretical finding also shows remarkable agreement with recent experimental reports, where spontaneous neural activity in the visual cortex without stimuli itinerate over evoked patterns by previously applied signals. Our results suggest that itinerant spontaneous activity can be a natural outcome of successive learning of several patterns, and it facilitates bifurcation of the network when an input is provided.

  6. Unusual presentation of spontaneous pneumomediastinum

    Directory of Open Access Journals (Sweden)

    Cho Tae

    2010-01-01

    Full Text Available Spontaneous pneumomediastinum (SPM is an uncommon, self-limiting condition resulting from alveolar rupture in young adults. There are asthma, illicit drug use, and activities triggering a Valsalva maneuver as causes of developing SPM. We report two patients who were diagnosed with SPM in the absence of known predisposing factors and without any clinical sign of subcutaneous emphysema of the neck, the most common physical finding on presentation. Both of them developed dysphagia after swallowing a peach seed and boned rib of pork, respectively. SPM was suspected after performing lateral neck X-ray, and the diagnosis of SPM was confirmed by chest CT. These cases showed the importance of performing the lateral neck X-ray to screen SPM in patients with dysphagia.

  7. Spontaneous Emission in Nonlocal Materials

    CERN Document Server

    Ginzburg, Pavel; Nasir, Mazhar E; Olvera, Paulina Segovia; Krasavin, Alexey V; Levitt, James; Hirvonen, Liisa M; Wells, Brian; Suhling, Klaus; Richards, David; Podolskiy, Viktor A; Zayats, Anatoly V

    2016-01-01

    Light-matter interactions can be dramatically modified by the surrounding environment. Here we report on the first experimental observation of molecular spontaneous emission inside a highly nonlocal metamaterial based on a plasmonic nanorod assembly. We show that the emission process is dominated not only by the topology of its local effective medium dispersion, but also by the nonlocal response of the composite, so that metamaterials with different geometric parameters but the same local effective medium properties exhibit different Purcell factors. A record-high enhancement of a decay rate is observed, in agreement with the developed quantitative description of the Purcell effect in a nonlocal medium. An engineered material nonlocality introduces an additional degree of freedom into quantum electrodynamics, enabling new applications in quantum information processing, photo-chemistry, imaging, and sensing.

  8. Spontaneous Emotional Facial Expression Detection

    Directory of Open Access Journals (Sweden)

    Zhihong Zeng

    2006-08-01

    Full Text Available Change in a speaker’s emotion is a fundamental component in human communication. Automatic recognition of spontaneous emotion would significantly impact human-computer interaction and emotion-related studies in education, psychology and psychiatry. In this paper, we explore methods for detecting emotional facial expressions occurring in a realistic human conversation setting—the Adult Attachment Interview (AAI. Because non-emotional facial expressions have no distinct description and are expensive to model, we treat emotional facial expression detection as a one- class classification problem, which is to describe target objects (i.e., emotional facial expressions and distinguish them from outliers (i.e., non-emotional ones. Our preliminary experiments on AAI data suggest that one-class classification methods can reach a good balance between cost (labeling and computing and recognition performance by avoiding non-emotional expression labeling and modeling.

  9. Decay modes in spontaneous fission

    CERN Document Server

    Gönnenwein, F

    1999-01-01

    Spontaneous fission (SF) is considered to be the choice reaction for studying the influence of shell and pairing effects in fission in general, and in particular their impact on the mass and energy distributions of fission fragments. For the time being some 35 SF reactions have been analysed in detail for elements ranging from Pu up to Rf. Going from the lighter to the heavier actinides both, the distributions of fragment mass (or charge) and of total kinetic energy undergo dramatic changes. It is observed in experiment, however, that these distributions may be well described as a superposition of a few fission modes, each with its own characteristic mass an energy pattern. The experimental modes are traced in theory to fine structures in the potential energy surface of a fissioning nucleus, provided shell and pairing corrections to the basic liquid drop model are accounted for.

  10. Cosmological Aspects of Spontaneous Baryogenesis

    CERN Document Server

    De Simone, Andrea

    2016-01-01

    We investigate cosmological aspects of spontaneous baryogenesis driven by a scalar field, and present general constraints that are independent of the particle physics model. The relevant constraints are obtained by studying the backreaction of the produced baryons on the scalar field, the cosmological expansion history after baryogenesis, and the baryon isocurvature perturbations. We show that cosmological considerations alone provide powerful constraints, especially for the minimal scenario with a quadratic scalar potential. Intriguingly, we find that for a given inflation scale, the other parameters including the reheat temperature, decoupling temperature of the baryon violating interactions, and the mass and decay constant of the scalar are restricted to lie within ranges of at most a few orders of magnitude. We also discuss possible extensions to the minimal setup, and propose two ideas for evading constraints on isocurvature perturbations: one is to suppress the baryon isocurvature with nonquadratic scal...

  11. Spontaneous germinal centers and autoimmunity.

    Science.gov (United States)

    Domeier, Phillip P; Schell, Stephanie L; Rahman, Ziaur S M

    2017-02-01

    Germinal centers (GCs) are dynamic microenvironments that form in the secondary lymphoid organs and generate somatically mutated high-affinity antibodies necessary to establish an effective humoral immune response. Tight regulation of GC responses is critical for maintaining self-tolerance. GCs can arise in the absence of purposeful immunization or overt infection (called spontaneous GCs, Spt-GCs). In autoimmune-prone mice and patients with autoimmune disease, aberrant regulation of Spt-GCs is thought to promote the development of somatically mutated pathogenic autoantibodies and the subsequent development of autoimmunity. The mechanisms that control the formation of Spt-GCs and promote systemic autoimmune diseases remain an open question and the focus of ongoing studies. Here, we discuss the most current studies on the role of Spt-GCs in autoimmunity.

  12. A New Venue of Spontaneous Supersymmetry Breaking in Supergravity

    CERN Document Server

    Guendelman, Eduardo; Pacheva, Svetlana; Vasihoun, Mahary

    2015-01-01

    We present a qualitatively new mechanism for dynamical spontaneous breakdown of supersymmetry in supergravity. Specifically, we construct a modified formulation of standard minimal N=1 supergravity as well as of anti-de Sitter supergravity in terms of a non-Riemannian spacetime volume-form (generally covariant integration measure density). The new supergravity formalism naturally triggers the appearance of a dynamically generated cosmological constant as an arbitrary integration constant which signifies spontaneous (dynamical) breaking of supersymmetry. Applying the new formalism to anti-de Sitter supergravity allows us to appropriately choose the above mentioned arbitrary integration constant so as to obtain simultaneously a very small effective observable cosmological constant as well as a large physical gravitino mass as required by modern cosmological scenarios for slowly expanding universe of the present epoch.

  13. Spontaneous Rupture of Pancreatic Pseudocyst: Report of Two Cases

    Directory of Open Access Journals (Sweden)

    Ricardo Rocha

    2016-01-01

    Full Text Available Introduction. Pancreatic pseudocysts are a common complication of acute pancreatitis. Pancreatic pseudocyst’s natural history ranges between its spontaneous regression and the settlement of serious complications if untreated, such as splenic complications, hemorrhage, infection, biliary complications, portal hypertension, and rupture. The rupture of a pancreatic pseudocyst to the peritoneal cavity is a dangerous complication leading to severe peritonitis and septic conditions. It requires emergent surgical exploration that is often of great technical difficulty and with important morbidity and mortality. Case Study. We present two cases of spontaneous rupture of pancreatic pseudocysts, managed differently according to the local and systemic conditions. Conclusion. The best surgical choice is the internal drainage of the cyst to the GI tract; however, in some conditions, the external drainage is the only choice available.

  14. Spontaneous synchronization driven by energy transport in interconnected networks

    CERN Document Server

    Nicosia, Vincenzo; Latora, Vito; Arenas, Alex

    2014-01-01

    The existence of intertwined dynamical processes in interconnected networks is a distinctive aspect of complex systems. For example, cerebral circulation delivers oxygenated blood to the brain through blood vessels, and in turn the neural system in the brain is responsible, through neural network connections, for mediating changes in cerebral blood flow. To understand the effects of the coupling between different processes we study the case of two interconnected networks, one accounting for energy transport and the other for a synchronization dynamics. We observe the emergence of switch-like spontaneous synchronization, similar to that seen in the transition between resting-state and cognitive activity in the human brain, for a wide range of control parameters and for different network topologies. We suggest that similarly interconnected dynamical processes could be responsible for spontaneous synchronization transitions observed in natural systems.

  15. Crows spontaneously exhibit analogical reasoning.

    Science.gov (United States)

    Smirnova, Anna; Zorina, Zoya; Obozova, Tanya; Wasserman, Edward

    2015-01-19

    Analogical reasoning is vital to advanced cognition and behavioral adaptation. Many theorists deem analogical thinking to be uniquely human and to be foundational to categorization, creative problem solving, and scientific discovery. Comparative psychologists have long been interested in the species generality of analogical reasoning, but they initially found it difficult to obtain empirical support for such thinking in nonhuman animals (for pioneering efforts, see [2, 3]). Researchers have since mustered considerable evidence and argument that relational matching-to-sample (RMTS) effectively captures the essence of analogy, in which the relevant logical arguments are presented visually. In RMTS, choice of test pair BB would be correct if the sample pair were AA, whereas choice of test pair EF would be correct if the sample pair were CD. Critically, no items in the correct test pair physically match items in the sample pair, thus demanding that only relational sameness or differentness is available to support accurate choice responding. Initial evidence suggested that only humans and apes can successfully learn RMTS with pairs of sample and test items; however, monkeys have subsequently done so. Here, we report that crows too exhibit relational matching behavior. Even more importantly, crows spontaneously display relational responding without ever having been trained on RMTS; they had only been trained on identity matching-to-sample (IMTS). Such robust and uninstructed relational matching behavior represents the most convincing evidence yet of analogical reasoning in a nonprimate species, as apes alone have spontaneously exhibited RMTS behavior after only IMTS training. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Timing of spontaneous sleep-paralysis episodes.

    Science.gov (United States)

    Girard, Todd A; Cheyne, J Allan

    2006-06-01

    The objective of this prospective naturalistic field study was to determine the distribution of naturally occurring sleep-paralysis (SP) episodes over the course of nocturnal sleep and their relation to bedtimes. Regular SP experiencers (N = 348) who had previously filled out a screening assessment for SP as well as a general sleep survey were recruited. Participants reported, online over the World Wide Web, using a standard reporting form, bedtimes and subsequent latencies of spontaneous episodes of SP occurring in their homes shortly after their occurrence. The distribution of SP episodes over nights was skewed to the first 2 h following bedtime. Just over one quarter of SP episodes occurred within 1 h of bedtime, although episodes were reported throughout the night with a minor mode around the time of normal waking. SP latencies following bedtimes were moderately consistent across episodes and independent of bedtimes. Additionally, profiles of SP latencies validated self-reported hypnagogic, hypnomesic, and hypnopompic SP categories, as occurring near the beginning, middle, and end of the night/sleep period respectively. Results are consistent with the hypothesis that SP timing is controlled by mechanisms initiated at or following sleep onset. These results also suggest that SP, rather than uniquely reflecting anomalous sleep-onset rapid eye movement (REM) periods, may result from failure to maintain sleep during REM periods at any point during the sleep period. On this view, SP may sometimes reflect the maintenance of REM consciousness when waking and SP hallucinations the continuation of dream experiences into waking life.

  17. Ovarian hyperstimulation syndrome in a spontaneous pregnancy ...

    African Journals Online (AJOL)

    Ovarian hyperstimulation syndrome in a spontaneous pregnancy with invasive mole: report of a case. ... Pan African Medical Journal ... in the case of multiple gestations, hypothyroidism or polycystic ovary syndrome. We report a case of severe OHSS in spontaneous pregnancy with invasive mole in a 34 years old woman.

  18. Spontaneous rupture of choledochal cyst: case report

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ho Seob; Nam, Kyung Jin; Lee, Jin Hwa; Kim, Chan Sung; Choi, Jong Cheol; Oh, Jong Young [Dong-a University College of Medicine, Pusan (Korea, Republic of)

    2002-11-01

    Spontaneous rupture of a choledochal cyst leading to biliary peritonitis is a rare complication which can be fatal if not promptly diagnosed. The authors report the ultrasound and CT findings of two cases of spontaneous choledochal cystic rupture and the biliary peritonitis which ensued.

  19. Genetics Home Reference: primary spontaneous pneumothorax

    Science.gov (United States)

    ... Spontaneous pneumothorax. BMJ. 2014 May 8;348:g2928. doi: 10.1136/bmj.g2928. Review. Citation on PubMed Chiu HT, Garcia CK. Familial spontaneous pneumothorax. Curr Opin Pulm Med. 2006 Jul;12(4):268-72. ... 2008 Nov;32(5):1316-20. doi: 10.1183/09031936.00132707. Epub 2008 Jun 25. ...

  20. Spontaneous emission near resonant optical antennas

    NARCIS (Netherlands)

    Frimmer, M.

    2012-01-01

    Martin Frimmer bouwde een nieuw type microscoop die de spontane emissie van een lichtbron kan peilen tijdens het scannen over een vlak monster. Daarbij kan een kaart van de emissie van de bron worden verkregen. De bron van spontane emissie is bevestigd aan een zogeheten scanning probe en kan worden

  1. Simultaneous and spontaneous bilateral quadriceps tendons rupture.

    Science.gov (United States)

    Celik, Evrim Coşkun; Ozbaydar, Mehmet; Ofluoglu, Demet; Demircay, Emre

    2012-07-01

    Simultaneous and spontaneous bilateral quadriceps tendon rupture is an uncommon injury that is usually seen in association with multiple medical conditions and some medications. We report a case of simultaneous and spontaneous bilateral quadriceps tendon rupture that may be related to the long-term use of a statin.

  2. La maladie de Grisel : Spontaneous atlantoaxial subluxation

    NARCIS (Netherlands)

    Meek, MF; Robinson, PH; Hermens, RAEC

    2001-01-01

    Objective: "La maladie de Grisel" (Grisel's syndrome) is a spontaneously occurring atlantoaxial subluxation with torticollis. We present a case of atlantoaxial subluxation occurring in a 20-year period of pharyngoplasty surgery. The occurrence of a "spontaneous" atlantoaxial subluxation after oral c

  3. "Spontaneous" Strategy Use: Perspectives from Metacognitive Theory.

    Science.gov (United States)

    Borkowski, John G.; And Others

    1987-01-01

    A metacognitive model was proposed as an explanatory framework for spontaneous strategy use. A study in which hyperactive children transferred newly acquired strategies following self-control training and attributional retraining served as an illustration of how components in the model can be used to better understand "spontaneity." (Author/LMO)

  4. Spontaneously Combustible Solids -- A Literature Search

    Science.gov (United States)

    1975-05-01

    the increasing acidity of the clay surface. Treatment of the clays with volatile organic’ bases or basic substances such as urea or...Stearic kcid heats spontaneously Straw of Flax, Maize , Oats, Rice, subject to spontaneous heating and Rye, Wheat, etc. combustion 22 NSWC/WOL/TR 75-159

  5. Early pregnancy angiogenic markers and spontaneous abortion

    DEFF Research Database (Denmark)

    Andersen, Louise B; Dechend, Ralf; Karumanchi, S Ananth

    2016-01-01

    BACKGROUND: Spontaneous abortion is the most commonly observed adverse pregnancy outcome. The angiogenic factors soluble Fms-like kinase 1 and placental growth factor are critical for normal pregnancy and may be associated to spontaneous abortion. OBJECTIVE: We investigated the association between...... maternal serum concentrations of soluble Fms-like kinase 1 and placental growth factor, and subsequent spontaneous abortion. STUDY DESIGN: In the prospective observational Odense Child Cohort, 1676 pregnant women donated serum in early pregnancy, gestational week ..., interquartile range 71-103). Concentrations of soluble Fms-like kinase 1 and placental growth factor were determined with novel automated assays. Spontaneous abortion was defined as complete or incomplete spontaneous abortion, missed abortion, or blighted ovum

  6. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  7. Entropy and spontaneity in an introductory physics course for life science students

    CERN Document Server

    Geller, Benjamin D; Gouvea, Julia; Sawtelle, Vashti; Turpen, Chandra; Redish, Edward F

    2013-01-01

    In an Introductory Physics for Life Science (IPLS) course that leverages authentic biological examples, student ideas about entropy as "disorder" or "chaos" come into contact with their ideas about the spontaneous formation of organized biological structure. It is possible to reconcile the "natural tendency to disorder" with the organized clustering of macromolecules, but doing so in a way that will be meaningful to students requires that we take seriously the ideas about entropy and spontaneity that students bring to IPLS courses from their prior experiences in biology and chemistry. We draw on case study interviews to argue that an approach that emphasizes the interplay of energy and entropy in determining spontaneity (one that involves a central role for free energy) is one that draws on students' resources from biology and chemistry in particularly effective ways. We see the positioning of entropic arguments alongside energetic arguments in the determination of spontaneity as an important step toward maki...

  8. Bilateral spontaneous hemotympanum: Case report

    Directory of Open Access Journals (Sweden)

    Economou Nicolas C

    2006-10-01

    Full Text Available Abstract Background The most common causes of hemotympanum are therapeutic nasal packing, epistaxis, blood disorders and blunt trauma to the head. Hemotympanum is characterized as idiopathic, when it is detected in the presence of chronic otitis media. A rare case of spontaneous bilateral hemotympanum in a patient treated with anticoagulants is presented herein. Case presentation A 72-year-old male presented with acute deterioration of hearing. In the patient's medical history aortic valve replacement 1 year before presentation was reported. Since then he had been administered regularly coumarinic anticoagulants, with INR levels maintained between 3.4 and 4.0. Otoscopy revealed the presence of bilateral hemotympanum. The audiogram showed symmetrical moderately severe mixed hearing loss bilaterally, with the conductive component predominating. Tympanograms were flat bilaterally with absent acoustic reflexes. A computerized tomography scan showed the presence of fluid in the mastoid and middle ear bilaterally. Treatment was conservative and consisted of a 10-day course of antibiotics, anticongestants and temporary interruption of the anticoagulant therapy. After 3 weeks, normal tympanic membranes were found and hearing had returned to previous levels. Conclusion Anticoagulant intake should be included in the differential diagnosis of hemotympanum, because its detection and appropriate treatment may lead to resolution of the disorder.

  9. Cosmological aspects of spontaneous baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Andrea De; Kobayashi, Takeshi [SISSA,Via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste,Via Bonomea 265, 34136 Trieste (Italy)

    2016-08-24

    We investigate cosmological aspects of spontaneous baryogenesis driven by a scalar field, and present general constraints that are independent of the particle physics model. The relevant constraints are obtained by studying the backreaction of the produced baryons on the scalar field, the cosmological expansion history after baryogenesis, and the baryon isocurvature perturbations. We show that cosmological considerations alone provide powerful constraints, especially for the minimal scenario with a quadratic scalar potential. Intriguingly, we find that for a given inflation scale, the other parameters including the reheat temperature, decoupling temperature of the baryon violating interactions, and the mass and decay constant of the scalar are restricted to lie within ranges of at most a few orders of magnitude. We also discuss possible extensions to the minimal setup, and propose two ideas for evading constraints on isocurvature perturbations: one is to suppress the baryon isocurvature with nonquadratic scalar potentials, another is to compensate the baryon isocurvature with cold dark matter isocurvature by making the scalar survive until the present.

  10. Simultaneous bilateral primary spontaneous pneumothorax

    Directory of Open Access Journals (Sweden)

    Arife Zeybek

    2014-04-01

    Full Text Available Simultaneous bilateral primary pneumothorax is a very rare (1.6 / 100,000 and life-threatening condition. Clinical presentation may vary from mild dyspnea to tension pneumothorax. It may be milder particularly in younger patients, but more severe in patients with advanced age, and tube thoracostomy is a life preserver in the latter group. Since mortality and recurrence rates following tube thoracostomy are high, endoscopic approaches to bilateral hemithorax have been reported in literature. Apical wedge resection and pleural procedures are recommended in video thoracoscopy or mini thoracotomy even if no bulla and/or bleb are detected. Bilateral surgical interventions and additional pleural procedures are associated with increased rate of post-operative complications and longer postoperative hospital-stays. As a first-line approach, the surgical method toward any side of lung with air leakage following a previous tube thoracostomy is considered less invasive, especially in younger patients. Here, we present a case of simultaneous bilateral primary spontaneous pneumothorax (SBPSP in a 21-year old male with no history of smoking and chronic pulmonary disease. A unilateral surgical intervention was performed, and no recurrence was observed during 5-year follow up.

  11. Nucleosomes undergo slow spontaneous gaping.

    Science.gov (United States)

    Ngo, Thuy T M; Ha, Taekjip

    2015-04-30

    In eukaryotes, DNA is packaged into a basic unit, the nucleosome which consists of 147 bp of DNA wrapped around a histone octamer composed of two copies each of the histones H2A, H2B, H3 and H4. Nucleosome structures are diverse not only by histone variants, histone modifications, histone composition but also through accommodating different conformational states such as DNA breathing and dimer splitting. Variation in nucleosome structures allows it to perform a variety of cellular functions. Here, we identified a novel spontaneous conformational switching of nucleosomes under physiological conditions using single-molecule FRET. Using FRET probes placed at various positions on the nucleosomal DNA to monitor conformation of the nucleosome over a long period of time (30-60 min) at various ionic conditions, we identified conformational changes we refer to as nucleosome gaping. Gaping transitions are distinct from nucleosome breathing, sliding or tightening. Gaping modes switch along the direction normal to the DNA plane through about 5-10 angstroms and at minutes (1-10 min) time scale. This conformational transition, which has not been observed previously, may be potentially important for enzymatic reactions/transactions on nucleosomal substrate and the formation of multiple compression forms of chromatin fibers.

  12. Spontaneous Metacognition in Rhesus Monkeys.

    Science.gov (United States)

    Rosati, Alexandra G; Santos, Laurie R

    2016-09-01

    Metacognition is the ability to think about thinking. Although monitoring and controlling one's knowledge is a key feature of human cognition, its evolutionary origins are debated. In the current study, we examined whether rhesus monkeys (Macaca mulatta; N = 120) could make metacognitive inferences in a one-shot decision. Each monkey experienced one of four conditions, observing a human appearing to hide a food reward in an apparatus consisting of either one or two tubes. The monkeys tended to search the correct location when they observed this baiting event, but engaged in information seeking-by peering into a center location where they could check both potential hiding spots-if their view had been occluded and information seeking was possible. The monkeys only occasionally approached the center when information seeking was not possible. These results show that monkeys spontaneously use information about their own knowledge states to solve naturalistic foraging problems, and thus provide the first evidence that nonhumans exhibit information-seeking responses in situations with which they have no prior experience.

  13. Cosmological aspects of spontaneous baryogenesis

    Science.gov (United States)

    De Simone, Andrea; Kobayashi, Takeshi

    2016-08-01

    We investigate cosmological aspects of spontaneous baryogenesis driven by a scalar field, and present general constraints that are independent of the particle physics model. The relevant constraints are obtained by studying the backreaction of the produced baryons on the scalar field, the cosmological expansion history after baryogenesis, and the baryon isocurvature perturbations. We show that cosmological considerations alone provide powerful constraints, especially for the minimal scenario with a quadratic scalar potential. Intriguingly, we find that for a given inflation scale, the other parameters including the reheat temperature, decoupling temperature of the baryon violating interactions, and the mass and decay constant of the scalar are restricted to lie within ranges of at most a few orders of magnitude. We also discuss possible extensions to the minimal setup, and propose two ideas for evading constraints on isocurvature perturbations: one is to suppress the baryon isocurvature with nonquadratic scalar potentials, another is to compensate the baryon isocurvature with cold dark matter isocurvature by making the scalar survive until the present.

  14. The role of innate immunity in spontaneous regression of cancer

    Directory of Open Access Journals (Sweden)

    J A Thomas

    2011-01-01

    Full Text Available Nature has provided us with infections - acute and chronic - and these infections have both harmful and beneficial effects on the human system. Worldwide, a number of chronic infections are associated with a risk of cancer, but it is also known that cancer regresses when associated with acute infections such as bacterial, viral, fungal, protozoal, etc. Acute infections are known to cure chronic diseases since the time of Hippocrates. The benefits of these fever producing acute infections has been applied in cancer vaccinology such as the Coley′s toxins. Immune cells like the natural killer cells, macrophages and dendritic cells have taken greater precedence in cancer immunity than ever before. This review provides an insight into the benefits of fever and its role in prevention of cancer, the significance of common infections in cancer regression, the dual nature of our immune system and the role of the often overlooked primary innate immunity in tumor immunology and spontaneous regression of cancer.

  15. The clinical and laboratory characteristics of acute spontaneous urticaria and its progression to chronic spontaneous urticaria.

    Science.gov (United States)

    Magen, Eli; Zueva, Ekaterina; Mishal, Joseph; Schlesinger, Menachem

    2016-09-01

    The natural history of the progression from acute spontaneous urticaria (ASU) to chronic spontaneous urticaria (CSU), CSU remains poorly understood. To identify clinical and laboratory patient attributes that may be predictive of ASU progression to CSU. We prospectively studied consecutive adult patients (age ≥ 18 years) with a diagnosis of urticaria of urticaria activity score assessment were performed in all the patients at baseline and then at weeks 7, 12, 24, and 48. Of 114 patients with acute urticaria and without identifiable causes, 73 patients (64%) were included in the ASU group, 41 patients in the CSU group (36%), and 44 healthy subjects in the control group. At baseline, 26 patients in the CSU group (63.4%) had a positive ASST result, whereas only 17 patients with a positive ASST result (23.3%) were revealed in the ASU group (p < 0.001). Patients with baseline ASST positive results were characterized by more profound basopenia (mean [standard deviation], 0.05 ± 0.08 cell/mm(3)) and more anti-thyroid peroxidase antibodies (18 [41.8%]) than those with the negative baseline ASST result (mean [standard deviation], 0.13 ± 0.09 cell/mm(3), p < 0.001 more profound basopenia; and 13 (18.1%), p = 0.009 more thyroid peroxidase antibodies). We observed the disappearance of ASST positive result in some patients with CSU with baseline positive ASST results, whereas, in some subjects with CSU, baseline negative ASST results came to be positive results throughout the study period. A baseline positive ASST result of patients with ASU was a significant determinant (odds ratio 5.91 [95% confidence interval, 2.57-13.62]; p < 0.001) for a CSU diagnosis at week 7. The patients with ASU who progressed toward CSU were characterized by a positive ASST result, thyroid autoimmunity, and profound basopenia at baseline.

  16. The cyanide gasp and spontaneous deep breaths.

    Science.gov (United States)

    Glogowska, M; Richardson, P S

    1973-01-01

    Stimulation of the carotid body chemoreceptors with cyanide in anaesthetized rabbits usually causes a deep breath or gasp, but only if the vagus nerves are intact. This gasp has several similarities with spontaneous deep breaths in eupnoea. In paralysed rabbits, artificially ventilated, chemoreceptor stimulation induces an augmented discharge in the phrenic nerve equivalent to a gasp. In spontaneously breathing rabbits spontaneous deep breaths are more frequent with hypoxia than with normoxia. The results are interpreted in relation to (i) positive feedback from the lungs and (ii) summation of chemoreceptor and tonic vagal drive causing augmented deep breaths.

  17. Roughening dynamics of spontaneous radial imbibition

    CERN Document Server

    Chen, Yong-Jun

    2015-01-01

    We performed an experimental observation on the spontaneous imbibition of water in a porous media in a radial Hele-Shaw cell and confirmed Washburn's law, where r is distance and t is time. Spontaneous imbibition with a radial interface window followed scaling dynamics when the front invaded into the porous media. We found a growth exponent (\\b{eta}=0.6) that was independent of the pressure applied at the liquid inlet. The roughness exponent decreased with an increase in pressure. The roughening dynamics of two dimensional spontaneous radial imbibition obey Family-Vicsek scaling, which is different from that with a one-dimensional planar interface window.

  18. Spontaneous Bacterial Peritonitis in Subclinical Hypothyroidism

    Directory of Open Access Journals (Sweden)

    Dalip Gupta

    2013-11-01

    Full Text Available Hypothyroidism is an uncommon cause of ascites. Here we describe a case of a 75 year-old female patient with spontaneous bacterial peritonitis and subclinical hypothyroidism that resolved with thyroid replacement and antibiotic therapy respectively. Ascitic fluid analysis revealed a gram-positive bacterium on gram staining. A review of the literature revealed just one other reported case of myxoedema ascites with concomitant spontaneous bacterial peritonitis and no case has till been reported of spontaneous bacterial peritonitis in subclinical hypothyroidism.

  19. Spontaneous oscillatory contraction (SPOC) of sarcomeres in skeletal muscle.

    Science.gov (United States)

    Ishiwata, S; Okamura, N; Shimizu, H; Anazawa, T; Yasuda, K

    1991-01-01

    Skeletal myofibrils spontaneously oscillate under a condition where ATP, ADP, and Pi coexist and the concentration of free Ca2+ is less than about 1 microM. Although this oscillation phenomenon called SPOC is apparently simple, the molecular mechanism seems to be complex. The SPOC condition and the space-time pattern of SPOC wave suggest that the dynamics of association and dissociation of Pi (ADP) is regulated by the mechanical strain imposed on actin and myosin; the enzymatic activity (ATPase) of actomyosin complex and the mechanical event (contraction) are thus coupled to each other. In this sense, the nature of the mechanochemical enzyme, actomyosin ATPase, is revealed in SPOC.

  20. Chorioretinal Atrophy after Spontaneous Resolution of Myopic Foveoschisis

    Directory of Open Access Journals (Sweden)

    Antonio García-Ben

    2014-01-01

    Full Text Available Myopic foveoschisis is one of the major complications of pathologic myopia, and it was most recently identified by new imaging modalities. During the natural evolution of this complication, anatomical and visual improvement without surgical intervention is an unusual course, and most of these eyes remain stable or progressively worsen. The authors report a case of a highly myopic eye that developed patchy chorioretinal atrophy after spontaneous resolution of myopic foveoschisis, which to the best of our knowledge has not been reported previously in the medical literature.

  1. Lunar Cycle Influences Spontaneous Delivery in Cows

    Science.gov (United States)

    Yonezawa, Tomohiro; Uchida, Mona; Tomioka, Michiko; Matsuki, Naoaki

    2016-01-01

    There is a popular belief that the lunar cycle influences spontaneous delivery in both humans and cattle. To assess this relationship, we investigated the synodic distribution of spontaneous deliveries in domestic Holstein cows. We used retrospective data from 428 spontaneous, full-term deliveries within a three-year period derived from the calving records of a private farm in Hokkaido, Japan. Spontaneous birth frequency increased uniformly from the new moon to the full moon phase and decreased until the waning crescent phase. There was a statistically significant peak between the waxing gibbous and full moon phases compared with those between the last quarter and the waning crescent. These changes were clearly observed in deliveries among multiparous cows, whereas they were not evident in deliveries among nulliparous cows. These data suggest the utility of dairy cows as models for bio-meteorological studies, and indicate that monitoring lunar phases may facilitate comprehensive understanding of parturition. PMID:27580019

  2. Spontaneous fission properties of superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Hessberger, F.P. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz-Institut Mainz, Mainz (Germany)

    2017-04-15

    Spontaneous fission properties of transuranium isotopes are reviewed. Specific emphasis was laid on brief historical overviews of theoretical descriptions and experimental determination of basic properties as spontaneous fission half-lives, fission barriers, or total kinetic energy release in fission. Experimental spontaneous fission half-lives are compared with the results of recent theoretical predictions. Hindrance factors for spontaneous fission of odd-mass nuclei are discussed in context with the configuration (spin, parity) of the fissioning states and the change in energy of single particle levels at deformation. Kinetic energy release and mass distributions are discussed in the context of different fission modes, as symmetric and asymmetric or fission from elongated or compact shapes of the nascent fission fragments. An overview of recent fission barrier calculations of superheavy elements on the basis of macroscopic-microscopic models or self-consistent calculations is given, and the results are compared for selected examples. (orig.)

  3. Lunar Cycle Influences Spontaneous Delivery in Cows.

    Science.gov (United States)

    Yonezawa, Tomohiro; Uchida, Mona; Tomioka, Michiko; Matsuki, Naoaki

    2016-01-01

    There is a popular belief that the lunar cycle influences spontaneous delivery in both humans and cattle. To assess this relationship, we investigated the synodic distribution of spontaneous deliveries in domestic Holstein cows. We used retrospective data from 428 spontaneous, full-term deliveries within a three-year period derived from the calving records of a private farm in Hokkaido, Japan. Spontaneous birth frequency increased uniformly from the new moon to the full moon phase and decreased until the waning crescent phase. There was a statistically significant peak between the waxing gibbous and full moon phases compared with those between the last quarter and the waning crescent. These changes were clearly observed in deliveries among multiparous cows, whereas they were not evident in deliveries among nulliparous cows. These data suggest the utility of dairy cows as models for bio-meteorological studies, and indicate that monitoring lunar phases may facilitate comprehensive understanding of parturition.

  4. Spontaneous Coronary Artery Dissection with Cardiac Tamponade.

    Science.gov (United States)

    Goh, Anne C H; Lundstrom, Robert J

    2015-10-01

    Spontaneous coronary artery dissection is a rare cause of acute coronary syndrome. Clinical presentation ranges from chest pain alone to ST-segment-elevation myocardial infarction, ventricular fibrillation, and sudden death. The treatment of patients with spontaneous coronary artery dissection is challenging because the disease pathophysiology is unclear, optimal treatment is unknown, and short- and long-term prognostic data are minimal. We report the case of a 70-year-old woman who presented with an acute ST-segment-elevation myocardial infarction secondary to a spontaneous dissection of the left anterior descending coronary artery. She was treated conservatively. Cardiac tamponade developed 16 hours after presentation. Repeat coronary angiography revealed extension of the dissection. Medical therapy was continued after the hemopericardium was aspirated. The patient remained asymptomatic 3 years after hospital discharge. To our knowledge, this is the first reported case of spontaneous coronary artery dissection in association with cardiac tamponade that was treated conservatively and had a successful outcome.

  5. Spontaneous Regression of an Incidental Spinal Meningioma

    National Research Council Canada - National Science Library

    Yilmaz, Ali; Kizilay, Zahir; Sair, Ahmet; Avcil, Mucahit; Ozkul, Ayca

    2015-01-01

    AIM: The regression of meningioma has been reported in literature before. In spite of the fact that the regression may be involved by hemorrhage, calcification or some drugs withdrawal, it is rarely observed spontaneously. CASE REPORT...

  6. Spontaneous splenic rupture in typhoid fever.

    OpenAIRE

    Ali, G; Kamili, M. A.; Rashid, S; Mansoor, A; Lone, B. A.; Allaqaband, G. Q.

    1994-01-01

    Three cases of multidrug-resistant Salmonella typhi infection presenting as spontaneous splenic rupture are presented. One patient died and two recovered completely. This is a previously unreported presentation of typhoid fever.

  7. Right Diaphragm Spontaneous Rupture: A Surgical Approach

    Directory of Open Access Journals (Sweden)

    Duilio Divisi

    2011-01-01

    Full Text Available We present a case of spontaneous rupture of the diaphragm, characterized by nonspecific symptoms. The rapid diagnosis and appropriate surgical approach led to a positive resolution of the pathology.

  8. SPONTANEOUS RESOLUTION OF ACUTE SUBDURAL HAEMATOMA

    Directory of Open Access Journals (Sweden)

    Ramandeep Singh

    2013-11-01

    Full Text Available ABSTRACT: We report a case of a 47 year old man who presented with head injury due to road traffi c accident, with CT scan suggestive of large left sided acute SDH with comminuted fracture of occipital bone. Within a few hours, patient showed significant neurological improvement. Follow - up CT scan revealed rapid spontaneous resolution and redistributio n of the acute SDH. The proposed hypothesis explaining this rare phenomenon suggests intracranial and extra cranial redistribution as the cause of spontaneous resolution of acute SDH. The intracranial phenomenon is more common of the two. To our knowledge, this is the first case in the literature where both intracranial and extracranial phenomenon played a role in the same patient leading to rapid spontaneous resolution of acute SDH KEY WORDS: ● acute subdural hematoma ● spontaneous resolution ● intracr anial redistribution ● extracranial redistribution

  9. Original article Spontaneous Pregnancy Outcome after Surgical ...

    African Journals Online (AJOL)

    2011-09-28

    Sep 28, 2011 ... FSH may predict the spontaneous pregnancy outcome. Key Words: Male infertility, ... The reasons for exclusion in 193 patients were subclinical varicocele (21) ... zinc, folic acid and vitamin B12 (Sigma-. Tau Health Science ...

  10. Spontaneous Trait Inferences on Social Media

    Science.gov (United States)

    Utz, Sonja

    2016-01-01

    The present research investigates whether spontaneous trait inferences occur under conditions characteristic of social media and networking sites: nonextreme, ostensibly self-generated content, simultaneous presentation of multiple cues, and self-paced browsing. We used an established measure of trait inferences (false recognition paradigm) and a direct assessment of impressions. Without being asked to do so, participants spontaneously formed impressions of people whose status updates they saw. Our results suggest that trait inferences occurred from nonextreme self-generated content, which is commonly found in social media updates (Experiment 1) and when nine status updates from different people were presented in parallel (Experiment 2). Although inferences did occur during free browsing, the results suggest that participants did not necessarily associate the traits with the corresponding status update authors (Experiment 3). Overall, the findings suggest that spontaneous trait inferences occur on social media. We discuss implications for online communication and research on spontaneous trait inferences. PMID:28123646

  11. Symptomatic Tarlov Cyst Following Spontaneous Subarachnoid Hemorrhage

    OpenAIRE

    Kong, Woo Keun; Cho, Keun-Tae; Hong, Seung-Koan

    2011-01-01

    Most of Tarlov or perineurial cysts remain asymptomatic throughout the patient's life. The pathogenesis is still unclear. Hemorrhage has been suggested as one of the possible causes and trauma with resultant hemorrhage into subarachnoid space has been suggested as an origin of these cysts. However, Tarlov cysts related to spontaneous subarachnoid hemorrhage has not been reported. The authors report a case of Tarlov cyst which was symptomatic following spontaneous subarachnoid hemorrhage.

  12. Symptomatic tarlov cyst following spontaneous subarachnoid hemorrhage.

    Science.gov (United States)

    Kong, Woo Keun; Cho, Keun-Tae; Hong, Seung-Koan

    2011-08-01

    Most of Tarlov or perineurial cysts remain asymptomatic throughout the patient's life. The pathogenesis is still unclear. Hemorrhage has been suggested as one of the possible causes and trauma with resultant hemorrhage into subarachnoid space has been suggested as an origin of these cysts. However, Tarlov cysts related to spontaneous subarachnoid hemorrhage has not been reported. The authors report a case of Tarlov cyst which was symptomatic following spontaneous subarachnoid hemorrhage.

  13. Spontaneous intracranial epidural hematoma during rivaroxaban treatment

    Energy Technology Data Exchange (ETDEWEB)

    Ruschel, Leonardo Gilmone; Rego, Felipe Marques Monteiro do; Milano, Jeronimo Buzetti; Jung, Gustavo Simiano; Silva Junior, Luis Fernando; Ramina, Ricardo, E-mail: leonardoruschel@yahoo.com.br [Instituto de Neurologia de Curitiba (INC), Curitiba, PR (Brazil)

    2016-11-15

    According to our research, this is the first case described in the literature of spontaneous intracranial epidural hematoma secondary to the use of Xarelto®. Spontaneous intracranial epidural hematomas are rarely described in the literature. They are associated with infectious diseases of the skull, coagulation disorders, vascular malformations of the dura mater and metastasis to the skull. Long-term post-marketing monitoring and independent reports will probably detect the full spectrum of hemorrhagic complications of the use of rivaroxaban. (author)

  14. Spontaneous regression of metastatic Merkel cell carcinoma.

    LENUS (Irish Health Repository)

    Hassan, S J

    2010-01-01

    Merkel cell carcinoma is a rare aggressive neuroendocrine carcinoma of the skin predominantly affecting elderly Caucasians. It has a high rate of local recurrence and regional lymph node metastases. It is associated with a poor prognosis. Complete spontaneous regression of Merkel cell carcinoma has been reported but is a poorly understood phenomenon. Here we present a case of complete spontaneous regression of metastatic Merkel cell carcinoma demonstrating a markedly different pattern of events from those previously published.

  15. Spontaneous rupture of unscarred gravid uterus.

    Science.gov (United States)

    Gurudut, Kolala S; Gouda, Hareesh S; Aramani, Sunil C; Patil, Raju H

    2011-01-01

    Rupture of gravid uterus during pregnancy is a rare entity. Overall incidence of rupture of uterus during pregnancy is 0.07%. The maternal and fetal prognoses are bad especially when the rupture occurs in an unscarred uterus. Fortunately, the sole major risk factor of spontaneous rupture of unscarred uterus is preventable, which is "multiparity." In this article, we report the death of a pregnant woman and her unborn child because of spontaneous rupture of unscarred uterus.

  16. Role of Development of Spontaneity in Teambuilding

    Directory of Open Access Journals (Sweden)

    Andrii TROFIMOV

    2015-12-01

    Full Text Available The presentation lightens the results of testing a forming program of development of spontaneity as a mean of building a team. It was found that spontaneity and creativity are important components of interaction between team members. The study showed that spontaneity is needed in order to cope with unexpected situations and difficulties which would inevitably arise even in the most predictable situation among the well-coordinated team. Previous studies have indicated that members of the creative team interact freely with each other, inspire each other and work together purposefully. The program of development of spontaneity was developed and approved. Elements of Playback Theatre were used as the main component of spontaneity. Playback Theatre is a theater of improvisation and spontaneity, where viewers tell their stories, and the actors play them immediately on the scene. Directions of training actors of Playback Theatre include: the development of self-reflection, emotional sensitivity, interaction skills, creativity imagination and the ability to feel and hold one selves body and voice. The forming program consists of 6 blocks and is designed for 10 sessions. Based on the findings developed forming program of the development personality’s spontaneity can be considered as an effective means of building a team. During the program there was a process of personal development, together with the obvious process of teambuilding. This program can be useful and used for a wide range of applications in different contexts, which is reflected in the recommendations on the use of forming program of development of spontaneity.

  17. Spontaneous lung herniation after a single cough

    Energy Technology Data Exchange (ETDEWEB)

    Tack, D.; Delcour, C. [Dept. of Radiology, C. H. U. de Charleroi (Belgium); Wattiez, A. [Dept. of Pneumology, C. H. U. de Charleroi (Belgium); Schtickzelle, J.C. [Dept. of Emergency Medicine, C. H. U. de Charleroi (Belgium)

    2000-03-01

    Herniation of the lung is commonly caused by congenital rib abnormalities, blunt trauma, or thoracic surgery. Spontaneous hernias are rarely described in the literature. We report a case of a spontaneous intercostal pulmonary hernia following a single cough. In addition, a review of the literature is presented which outlines the classification, causes, and incidence of lung hernias. Some reference is made to possible methods of treatment. (orig.)

  18. Spontaneous tunable Turing pattern formation for coherent high-power THz radiation

    CERN Document Server

    Huang, Shu-Wei; Yang, Shang-Hua; Yu, Mingbin; Kwong, Dim-Lee; Zelevinsky, T; Jarrahi, Mona; Wong, Chee Wei

    2016-01-01

    The spontaneous breaking of symmetry and homogeneity through dissipative pattern formation is a fundamental question in developmental biology, molecular biochemistry, mathematics and nonlinear physics. Self-organized patterns arise in nature, such as pigmentation in animals, tree branching fractals, Prigogine non-equilibrium chemical bifurcations, and are postulated by Turing to occur from diffusion-reaction driven instabilities. In spite of the spontaneous nature, these threshold-dependent patterns - when formed - can potentially be remarkably robust in the presence of noise. Here we report the spontaneous Turing pattern formation in chip-scale nonlinear oscillators, developing a precision frequency comb in the solid-state. The stationary Turing pattern is discretely tunable across 430 GHz on a THz carrier, with a sideband non-uniformity measured down to 1 part in 1.5x10^15. Local mode hybridizations in the nonlinear ring oscillator seeds the coherent pattern formation and phase matching, to obtain a record ...

  19. Spontaneous Vesicle Recycling in the Synaptic Bouton

    Directory of Open Access Journals (Sweden)

    Sven eTruckenbrodt

    2014-12-01

    Full Text Available The trigger for synaptic vesicle exocytosis is Ca2+, which enters the synaptic bouton following action potential stimulation. However, spontaneous release of neurotransmitter also occurs in the absence of stimulation in virtually all synaptic boutons. It has long been thought that this represents exocytosis driven by fluctuations in local Ca2+ levels. The vesicles responding to these fluctuations are thought to be the same ones that release upon stimulation, albeit potentially triggered by different Ca2+ sensors. This view has been challenged by several recent works, which have suggested that spontaneous release is driven by a separate pool of synaptic vesicles. Numerous articles appeared during the last few years in support of each of these hypotheses, and it has been challenging to bring them into accord. We speculate here on the origins of this controversy, and propose a solution that is related to developmental effects. Constitutive membrane traffic, needed for the biogenesis of vesicles and synapses, is responsible for high levels of spontaneous membrane fusion in young neurons, probably independent of Ca2+. The vesicles releasing spontaneously in such neurons are not related to other synaptic vesicle pools and may represent constitutively releasing vesicles (CRVs rather than bona fide synaptic vesicles. In mature neurons, constitutive traffic is much dampened, and the few remaining spontaneous release events probably represent bona fide spontaneously releasing synaptic vesicles (SRSVs responding to Ca2+ fluctuations, along with a handful of CRVs that participate in synaptic vesicle turnover.

  20. Spontaneous vesicle recycling in the synaptic bouton.

    Science.gov (United States)

    Truckenbrodt, Sven; Rizzoli, Silvio O

    2014-01-01

    The trigger for synaptic vesicle exocytosis is Ca(2+), which enters the synaptic bouton following action potential stimulation. However, spontaneous release of neurotransmitter also occurs in the absence of stimulation in virtually all synaptic boutons. It has long been thought that this represents exocytosis driven by fluctuations in local Ca(2+) levels. The vesicles responding to these fluctuations are thought to be the same ones that release upon stimulation, albeit potentially triggered by different Ca(2+) sensors. This view has been challenged by several recent works, which have suggested that spontaneous release is driven by a separate pool of synaptic vesicles. Numerous articles appeared during the last few years in support of each of these hypotheses, and it has been challenging to bring them into accord. We speculate here on the origins of this controversy, and propose a solution that is related to developmental effects. Constitutive membrane traffic, needed for the biogenesis of vesicles and synapses, is responsible for high levels of spontaneous membrane fusion in young neurons, probably independent of Ca(2+). The vesicles releasing spontaneously in such neurons are not related to other synaptic vesicle pools and may represent constitutively releasing vesicles (CRVs) rather than bona fide synaptic vesicles. In mature neurons, constitutive traffic is much dampened, and the few remaining spontaneous release events probably represent bona fide spontaneously releasing synaptic vesicles (SRSVs) responding to Ca(2+) fluctuations, along with a handful of CRVs that participate in synaptic vesicle turnover.

  1. FEL gain optimisation and spontaneous radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bali, L.M.; Srivastava, A.; Pandya, T.P. [Lucknow Univ. (India)] [and others

    1995-12-31

    Colson have evaluated FEL gains for small deviations from perfect electron beam injection, with radiation of the same polarisation as that of the wiggler fields. We find that for optimum gain the polarisation of the optical field should be the same as that of the spontaneous emission under these conditions. With a helical wiggler the axial oscillations resulting from small departures from perfect electron beam injection lead to injection dependent unequal amplitudes and phases of the spontaneous radiation in the two transverse directions. Viewed along the axis therefore the spontaneous emission is elliptically polarised. The azimuth of the ellipse varies with the difference of phase of the two transverse components of spontaneous emission but the eccentricity remains the same. With planar wigglers the spontaneous emission viewed in the axial direction is linearly polarised, again with an injection dependent azimuth. For optimum coherent gain of a radiation field its polarisation characteristics must be the same as those of the spontaneous radiation with both types of wiggler. Thus, with a helical wiggler and the data reported earlier, an increase of 10% in the FEL gain at the fundamental frequency and of 11% at the fifth harmonic has been calculated in the small gain per pass limit. Larger enhancements in gain may result from more favourable values of input parameters.

  2. Frequencies of spontaneous breast development and spontaneous menarche in Turner syndrome in Japan.

    Science.gov (United States)

    Tanaka, Toshiaki; Igarashi, Yutaka; Ozono, Keiichi; Ohyama, Kenji; Ogawa, Masamichi; Osada, Hisao; Onigata, Kazumichi; Kanzaki, Susumu; Kohno, Hitoshi; Seino, Yoshiki; Takahashi, Hiroaki; Tajima, Toshihiro; Tachibana, Katsuhiko; Tanaka, Hiroyuki; Nishi, Yoshikazu; Hasegawa, Tomonobu; Fujita, Keinosuke; Yorifuji, Tohru; Horikawa, Reiko; Yokoya, Susumu

    2015-10-01

    The Growject® database on human GH treatment in Turner syndrome was analyzed in the Turner Syndrome Research Collaboration, and the relationships of the frequencies of spontaneous breast development and spontaneous menarche with karyotype and GH treatment were investigated. One hundred and three cases started GH treatment with 0.5 IU/kg/ week (0.5 IU group), and their dose was increased to 0.35 mg/kg/wk midway through the treatment course. Another 109 cases started GH at a dose of 0.35 mg/kg/wk (0.35 mg group). Spontaneous breast development was observed in 77 (36.3%) of the 212 patients, and spontaneous menarche occurred in 31 patients (14.6%). The frequency of spontaneous breast development was significantly lower in patients with the 45,X karyotype and significantly higher in patients with a structural abnormality of the second X chromosome. The frequency of spontaneous menarche was significantly higher in patients with mosaicism characterized by X monosomy and a cellular line with no structural abnormality of the X chromosome. No significant differences in frequencies of spontaneous breast development and spontaneous menarche were observed between the two dose groups, indicating that GH treatment does not increase the frequency of spontaneous puberty.

  3. In vitro spontaneous differentiation of human breast cancer stem cells and methods to control this process

    Directory of Open Access Journals (Sweden)

    Phuc Van Pham

    2015-06-01

    Full Text Available Breast cancer stem cells were considered as origins of breast cancer. Previously published studies showed that breast cancer stem cells exhibited high multi-drug resistance. This study aimed to evaluate the spontaneous differentiation of human breast cancer stem cells and investigate some in vitro conditions to control this process. Human breast cancer stem cells (BCSCs were sorted from primary culture of breast malignant tumors based on expression of CD44 and CD24. The in vitro spontaneous differentiation of BCSCs was evaluated in the popular culture medium DMEM/F12 supplemented with 10% fetal bovine serum (FBS, 1% antibiotic-antimycotic. There were some different methods to control the spontaneous differentiation of BCSCs included free serum culture, mammosphere culture, basic fibroblast growth factor and epidermal growth factor supplement to serum medium, and hypoxia culture. The results showed that BCSCs always were spontaneously differentiated in vitro in the popular culture medium DMEM/F12 plus 10% FBS. The percentage of BCSCs gradually decreased according to sub-culture times and became stable after 20 sub-culture times. All investigated methods could not completely inhibit the spontaneous differentiation of BCSCs. Serum-free culture combined with hypoxia condition had strongest inhibition of this process. These results demonstrated that the spontaneous differentiation is nature process of BCSCs; therefore this process should be determined and suitably controlled depending on different experiments. [Biomed Res Ther 2015; 2(6.000: 290-296

  4. Spontaneous emission from a microwave-driven four-level atom in an anisotropic photonic crystal

    Science.gov (United States)

    Jiang, Li; Wan, Ren-Gang; Yao, Zhi-Hai

    2016-10-01

    The spontaneous emission from a microwave-driven four-level atom embedded in an anisotropic photonic crystal is studied. Due to the modified density of state (DOS) in the anisotropic photonic band gap (PBG) and the coherent control induced by the coupling fields, spontaneous emission can be significantly enhanced when the position of the spontaneous emission peak gets close to the band gap edge. As a result of the closed-loop interaction between the fields and the atom, the spontaneous emission depends on the dynamically induced Autler-Townes splitting and its position relative to the PBG. Interesting phenomena, such as spectral-line suppression, enhancement and narrowing, and fluorescence quenching, appear in the spontaneous emission spectra, which are modulated by amplitudes and phases of the coherently driven fields and the effect of PBG. This theoretical study can provide us with more efficient methods to manipulate the atomic spontaneous emission. Project supported by the National Natural Science Foundation of China (Grant Nos. 11447232, 11204367, 11447157, and 11305020).

  5. Improving Natural Uranium Utilization By Using Thorium in Low Moderation PWRs - A Preliminary Neutronic Scoping Study

    Energy Technology Data Exchange (ETDEWEB)

    Gilles Youinou; Ignacio Somoza

    2010-10-01

    The Th-U fuel cycle is not quite self-sustainable when used in water-cooled reactors and with fuel burnups higher than a few thousand of MWd/t characteristic of CANDU reactors operating with a continuous refueling. For the other industrially mature water-cooled reactors (i.e. PWRs and BWRs) it is economically necessary that the fuel has enough reactivity to reach fuel burnups of the order of a few tens of thousand of MWd/t. In this particular case, an additional input of fissile material is necessary to complement the bred fissile U-233. This additional fissile material could be included in the form of Highly Enriched Uranium (HEU) at the fabrication of the Th-U fuel. The objective of this preliminary neutronic scoping study is to determine (1) how much HEU and, consequently, how much natural uranium is necessary in such Th-U fuel cycle with U recycling and (2) how much TRansUranics (TRU=Pu, Np, Am and Cm) are produced. These numbers are then compared with those of a standard UO2 PWR. The thorium reactors considered have a homogeneous hexagonal lattice made up of the same (Th-U)O2 pins. Furthermore, at this point, we are not considering the use of blankets inside or outside the core. The lattice pitch has been varied to estimate the effect of the water-to-fuel volume ratio, and light water as well as heavy water have been considered. For most cases, an average burnup at discharge of 45,000 MWd/t has been considered.

  6. Molecular Darwinism: the contingency of spontaneous genetic variation.

    Science.gov (United States)

    Arber, Werner

    2011-01-01

    The availability of spontaneously occurring genetic variants is an important driving force of biological evolution. Largely thanks to experimental investigations by microbial geneticists, we know today that several different molecular mechanisms contribute to the overall genetic variations. These mechanisms can be assigned to three natural strategies to generate genetic variants: 1) local sequence changes, 2) intragenomic reshuffling of DNA segments, and 3) acquisition of a segment of foreign DNA. In these processes, specific gene products are involved in cooperation with different nongenetic elements. Some genetic variations occur fully at random along the DNA filaments, others rather with a statistical reproducibility, although at many possible sites. We have to be aware that evolution in natural ecosystems is of higher complexity than under most laboratory conditions, not at least in view of symbiotic associations and the occurrence of horizontal gene transfer. The encountered contingency of genetic variation can possibly best ensure a long-term persistence of life under steadily changing living conditions.

  7. Coherent spontaneous emission and spontaneous phase locking in a free-electron laser

    NARCIS (Netherlands)

    Weits, H. H.; Oepts, D.

    1999-01-01

    We present measurements that demonstrate the existence of spontaneous coherence between independently generated laser pulses in the FELIX free-electron laser, The experiments show that the interpulse coherence is caused by a high level of coherently enhanced spontaneous emission. We have been able t

  8. Smart and easy: Co-occurring activation of spontaneous trait inferences and spontaneous situational inferences

    NARCIS (Netherlands)

    Ham, J.R.C.; Vonk, R.

    2003-01-01

    Social perceivers have been shown to draw spontaneous trait inferences (STI's) about the behavior of an actor as well as spontaneous situational inferences (SSI's) about the situation the actor is in. In two studies, we examined inferences about behaviors that allow for both an STI and an SSI. In

  9. Spontaneous body movements in spatial cognition

    Directory of Open Access Journals (Sweden)

    Sergiu eTcaci Popescu

    2012-05-01

    Full Text Available People often perform spontaneous body movements during spatial tasks such as giving complex directions or orienting themselves on maps. How are these spontaneous gestures related to spatial problem-solving? We measured spontaneous movements during a perspective-taking task inspired by map reading. Analyzing the motion data to isolate rotation and translation components of motion in specific geometric relation to the task, we found out that most participants executed spontaneous miniature rotations of the head that were significantly related to the main task parameter. These head rotations were as if participants were trying to align themselves with the orientation on the map either in the image plane or on the ground plane, but with tiny amplitudes, typically below 1% of the actual movements. Our results are consistent with a model of sensorimotor prediction driving spatial reasoning. The efference copy of planned movements triggers this prediction mechanism. The movements themselves may then be mostly inhibited; the small spontaneous gestures that we measure are the visible traces of these planned but inhibited actions.

  10. Hyperprolactinemia due to spontaneous intracranial hypotension.

    Science.gov (United States)

    Schievink, Wouter I; Nuño, Miriam; Rozen, Todd D; Maya, M Marcel; Mamelak, Adam N; Carmichael, John; Bonert, Vivien S

    2015-05-01

    OBJECT Spontaneous intracranial hypotension is an increasingly recognized cause of headaches. Pituitary enlargement and brain sagging are common findings on MRI in patients with this disorder. The authors therefore investigated pituitary function in patients with spontaneous intracranial hypotension. METHODS Pituitary hormones were measured in a group of 42 consecutive patients with spontaneous intracranial hypotension. For patients with hyperprolactinemia, prolactin levels also were measured following treatment. Magnetic resonance imaging was performed prior to and following treatment. RESULTS The study group consisted of 27 women and 15 men with a mean age at onset of symptoms of 52.2 ± 10.7 years (mean ± SD; range 17-72 years). Hyperprolactinemia was detected in 10 patients (24%), ranging from 16 ng/ml to 96.6 ng/ml in men (normal range 3-14.7 ng/ml) and from 31.3 ng/ml to 102.5 ng/ml in women (normal range 3.8-23.2 ng/ml). In a multivariate analysis, only brain sagging on MRI was associated with hyperprolactinemia. Brain sagging was present in 60% of patients with hyperprolactinemia and in 19% of patients with normal prolactin levels (p = 0.02). Following successful treatment of the spontaneous intracranial hypotension, hyperprolactinemia resolved, along with normalization of brain MRI findings in all 10 patients. CONCLUSIONS Spontaneous intracranial hypotension is a previously undescribed cause of hyperprolactinemia. Brain sagging causing distortion of the pituitary stalk (stalk effect) may be responsible for the hyperprolactinemia.

  11. Effect of the spontaneous fermentation and the ageing on the chemo-sensory quality of Brazilian organic cachaça Efeito da fermentação natural e do envelhecimento sobre a qualidade química e sensorial de cachaça orgânica Brasileira

    Directory of Open Access Journals (Sweden)

    Afra Vital Matos Dias Gabriel

    2012-05-01

    Full Text Available This study verified the effect of the spontaneous fermentation/natural ferment (NF on the chemo-sensory quality of cachaça, comparing to the commercial ferment (CF. The effect of ageing (maturation was also analysed in the beverage. Microbiological analysis (plating on selective media for total/wild yeast and bacteria counting and physico-chemical analysis (pH, acidity and soluble solids were performed in the samples of the must and the ferment collected during three cycles of fermentation in a semi-industrial scale. Samples of cachaça were stored in 5-L oak containers for 45 days, subsequently analyzing the physico-chemical characteristics (pH, acidity, alcohol content, copper and secondary compounds and sensory acceptability (aroma, flavour, colour, body and global impression. The fermentation with NF showed higher number of wild yeasts; however there was no difference in the number of bacteria comparing to CF. An intense acidification occurred during the preparation of NF, which was also observed in the initial cycles of fermentation, but decreased afterwards. Greater alterations in cachaça composition were found to be more exclusively related to the maturation than to the type of ferment, except for the acidity. However, there was a significant loss of aroma, flavour and global impression after maturation but only in cachaça produced with the CF. The results revealed a strong interaction between ferment and maturation of the beverage, suggesting that substances produced by the microorganisms from different inocula during fermentation reacted differently with the wood components of the barrels influencing the sensory attributes.Este trabalho teve por objetivo avaliar o efeito da fermentação espontânea/fermento natural (NF sobre a qualidade fisico-química e aceitabilidade da cachaça, comparando-se com o fermento comercial (CF. O efeito do envelhecimento (maturação da bebida foi também avaliado. Análises microbiol

  12. Spontaneous Regression of an Incidental Spinal Meningioma

    Directory of Open Access Journals (Sweden)

    Ali Yilmaz

    2015-12-01

    Full Text Available AIM: The regression of meningioma has been reported in literature before. In spite of the fact that the regression may be involved by hemorrhage, calcification or some drugs withdrawal, it is rarely observed spontaneously. CASE REPORT: We report a 17 year old man with a cervical meningioma which was incidentally detected. In his cervical MRI an extradural, cranio-caudal contrast enchanced lesion at C2-C3 levels of the cervical spinal cord was detected. Despite the slight compression towards the spinal cord, he had no symptoms and refused any kind of surgical approach. The meningioma was followed by control MRI and it spontaneously regressed within six months. There were no signs of hemorrhage or calcification. CONCLUSION: Although it is a rare condition, the clinicians should consider that meningiomas especially incidentally diagnosed may be regressed spontaneously.

  13. Spontaneous Regression of an Incidental Spinal Meningioma.

    Science.gov (United States)

    Yilmaz, Ali; Kizilay, Zahir; Sair, Ahmet; Avcil, Mucahit; Ozkul, Ayca

    2016-03-15

    The regression of meningioma has been reported in literature before. In spite of the fact that the regression may be involved by hemorrhage, calcification or some drugs withdrawal, it is rarely observed spontaneously. We report a 17 year old man with a cervical meningioma which was incidentally detected. In his cervical MRI an extradural, cranio-caudal contrast enchanced lesion at C2-C3 levels of the cervical spinal cord was detected. Despite the slight compression towards the spinal cord, he had no symptoms and refused any kind of surgical approach. The meningioma was followed by control MRI and it spontaneously regressed within six months. There were no signs of hemorrhage or calcification. Although it is a rare condition, the clinicians should consider that meningiomas especially incidentally diagnosed may be regressed spontaneously.

  14. Spontaneous Perforation of Pyometra: A Case Report

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available Pyometra is the accumulation of purulent material in the uterine cavity. Its reported incidence is 0.01–0.5% in gynecologic patients; however, as far as elderly patients are concerned, its incidence is 13.6% [3]. The most common cause of pyometra is malignant diseases of genital tract and the consequences of their treatment (radiotherapy. Other causes are benign tumors like leiomyoma, endometrial polyps, senile cervicitis, cervical occlusion after surgery, puerperal infections, and congenital cervical anomalies. Spontaneous rupture of the uterus is an extremely rare complication of pyometra. To our knowledge, only 21 cases of spontaneous perforation of pyometra have been reported in English literature since 1980. This paper reports an additional case of spontaneous uterine rupture.

  15. Gravid med spontan ruptur af arteria uterina

    DEFF Research Database (Denmark)

    Jònsdòttir, Fjòla; Pinborg, Anja; Wilken-Jensen, Charlotte

    2014-01-01

    Pregnant women with acute abdominal pain are a clinical challenge. We present a rare but potential life-threatening condition of a pregnant woman with acute abdominal pain. The woman was in gestational week 37 with severe abdominal pain and was admitted to the labour ward. She became haemo......-dynamic instable 24 hours after vaginal delivery, and emergency laparotomi revealed a spontaneous rupture of the right uterine artery. Spontaneous rupture of the uterine artery is rare but should be considered as a possible cause of acute abdominal pain in pregnant women....

  16. Spontaneous pnemomedastinum in acute severe asthma

    Directory of Open Access Journals (Sweden)

    Aleemuddin N

    2010-01-01

    Full Text Available Spontaneous medastinal emphysema, as a complication of acute severe asthma, is an uncommon entity. It usually runs a benign course and resolves spontaneously without any surgical intervention. Recognition of this complication is critical, as it has to be differentiated from other life threatening ones including oesophageal rupture, Boerhave′s syndrome, acute coronary syndrome and pulmonary embolism. This case is being presented to emphasize its recognition in the differential diagnosis of complications arising from acute severe asthma and to present its management strategy in detail.

  17. Glycemia in Spontaneous Intracerebral Hemorrhage: Clinical Implications

    Directory of Open Access Journals (Sweden)

    Alvis-Miranda Hernando

    2014-10-01

    Full Text Available Spontaneous cerebral hemorrhage or intracranial hemorrhage accounts for 10-15% of all strokes. Intracranial hemorrhage is much less common than ischemic stroke, but has higher mortality and morbidity, one of the leading causes of severe disability. Various alterations, among these the endocrine were identified when an intracerebral hemorrhage, these stress-mediated mechanisms exacerbate secondary injury. Deep knowledge of the injuries which are directly involved alterations of glucose, offers insight as cytotoxicity, neuronal death and metabolic dysregulations alter the prognosis of patients with spontaneous intracerebral hemorrhage.

  18. Spontaneous abortion and physical strain around implantation

    DEFF Research Database (Denmark)

    Hjollund, N H; Jensen, Tina Kold; Bonde, Jens Peter

    2000-01-01

    Existing studies of physical strain and spontaneous abortion are mainly retrospective or based only on pregnancies that have survived the first trimester. Furthermore, almost all studies have relied on averaged measures of physical strain, which tend to blur an effect if peak values during short...... pregnancy the women recorded physical strain prospectively in a structured diary. Physical strain around the time of implantation was associated with later spontaneous abortion. The adjusted risk ratio for women who reported physical strain higher than average at day 6 to 9 after the estimated date...

  19. Primer on spontaneous heating and pyrophoricity

    Energy Technology Data Exchange (ETDEWEB)

    1994-12-01

    This primer was prepared as an information resource for personnel responsible for operation of DOE nuclear facilities. It has sections on combustion principles, spontaneous heating/ignition of hydrocarbons and organics, pyrophoric gases and liquids, pyrophoric nonmetallic solids, pyrophoric metals (including Pu and U), and accident case studies. Although the information in this primer is not all-encompassing, it should provide the reader with a fundamental knowledge level sufficient to recognize most spontaneous combustion hazards and how to prevent ignition and widespread fires. This primer is provided as an information resource only, and is not intended to replace any fire protection or hazardous material training.

  20. Spontaneous supersymmetry breaking on the lattice

    Energy Technology Data Exchange (ETDEWEB)

    Wenger, Urs [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

    2013-07-01

    We discuss various strategies for regularising supersymmetric quantum field theories on a space-time lattice. In general, simulations of lattice models with spontaneously broken supersymmetry suffer from a fermion sign problem related to the vanishing of the Witten index. We discuss a novel approach which evades this problem in low dimensions by formulating the path integral on the lattice in terms of fermion loops. Then we present exact results on the spectrum and the Witten index for N=2 supersymmetric quantum mechanics and results from simulations of the spontaneously broken N=1 Wess-Zumino model.

  1. Spontaneous sidebanding in high speed rotordynamics

    Science.gov (United States)

    Ehrich, F. F.

    1992-10-01

    It is noted that the spontaneous sideband spacing frequency seems to be a whole number fraction (1/J) of the operating speed which indicates that the wave form is periodic and completes a full cycle every J rotations of the rotor. Employing a numerical model of a rotor that simulates local contact with a stator in close proximity as a bilinear spring, studies have been conducted to explore the circumstances for this spontaneous sidebanding. Two general classes of this type of response are determined in a system that is effectively single-degree-of-freedom.

  2. Spontaneous abortion and physical strain around implantation

    DEFF Research Database (Denmark)

    Hjøllund, Niels Henrik Ingvar; Jensen, T.K.; Bonde, J.P.

    2000-01-01

    Existing studies of physical strain and spontaneous abortion are mainly retrospective or based only on pregnancies that have survived the first trimester. Furthermore, almost all studies have relied on averaged measures of physical strain, which tend to blur an effect if peak values during short...... pregnancy the women recorded physical strain prospectively in a structured diary. Physical strain around the time of implantation was associated with later spontaneous abortion. The adjusted risk ratio for women who reported physical strain higher than average at day 6 to 9 after the estimated date...

  3. Spontaneous Activity Characteristics of 3D “Optonets”

    Science.gov (United States)

    Marom, Anat; Shor, Erez; Levenberg, Shulamit; Shoham, Shy

    2017-01-01

    Sporadic spontaneous network activity emerges during early central nervous system (CNS) development and, as the number of neuronal connections rises, the maturing network displays diverse and complex activity, including various types of synchronized patterns. These activity patterns have major implications on both basic research and the study of neurological disorders, and their interplay with network morphology tightly correlates with developmental events such as neuronal differentiation, migration and establishment of neurotransmitter phenotypes. Although 2D neural cultures models have provided important insights into network activity patterns, these cultures fail to mimic the complex 3D architecture of natural CNS neural networks and its consequences on connectivity and activity. A 3D in-vitro model mimicking early network development while enabling cellular-resolution observations, could thus significantly advance our understanding of the activity characteristics in the developing CNS. Here, we longitudinally studied the spontaneous activity patterns of developing 3D in-vitro neural network “optonets,” an optically-accessible bioengineered CNS model with multiple cortex-like characteristics. Optonet activity was observed using the genetically encodable calcium indicator GCaMP6m and a 3D imaging solution based on a standard epi-fluorescence microscope equipped with a piezo-electric z-stage and image processing-based deconvolution. Our results show that activity patterns become more complex as the network matures, gradually exhibiting longer-duration events. This report characterizes the patterns over time, and discusses how environmental changes affect the activity patterns. The relatively high degree of similarity between the network's spontaneously generated activity patterns and the reported characteristics of in-vivo activity, suggests that this is a compelling model system for brain-in-a chip research. PMID:28119555

  4. Les transitions énergétiques urbaines du XIXe au XXIe siècle : de la biomasse aux combustibles fossiles et fissiles à Paris (France).

    OpenAIRE

    Kim, Eun Hye

    2013-01-01

    Increasing urban natural resource consumption and particularly fossil energy consumption is one of the important factors of global environment alteration. To understand the socioecological transition process for the city, we characterize it as a natral resource dependant system in material and ecological terms. Cities rnobilize a technical system to draw the external natural resource. Therefore, externality is a fundamental character of urban metabolism. We focus in this work on the relations...

  5. Spontaneous Hybridization between Pinus mugo and Pinus sylvestris at the Lithuanian Seaside: A Morphological Survey

    Directory of Open Access Journals (Sweden)

    Darius Danusevičius

    2012-01-01

    Full Text Available We address the problem of spontaneous hybridization between an exotic species Pinus mugo and the native/local P. sylvestris at the seaside spit of Kursiu Nerija in Lithuania. The objective was to identify spontaneous hybrids between P. mugo and P. sylvestris based on morphology traits among the individuals naturally regenerating at the seaside spit. The field inventory was carried out over the entire Lithuanian part of the spit, and 200 individuals morphologically intermediate between P. sylvestris and P. mugo were identified. Based on a weighted trait index, the intermediate individuals were grouped into two groups, one morphologically close to P. sylvestris and another close to P. mugo. The needle micromorphological traits of the putative hybrids were of intermediate values between P. mugo and P. sylvestris. The results provide a strong evidence of spontaneous hybridization between P. mugo and P. sylvestris in Lithuanian seaside spit of Kursiu Nerija.

  6. Spontaneous hybridization between Pinus mugo and Pinus sylvestris at the Lithuanian seaside: a morphological survey.

    Science.gov (United States)

    Danusevičius, Darius; Marozas, Vitas; Brazaitis, Gediminas; Petrokas, Raimundas; Christensen, Knud Ib

    2012-01-01

    We address the problem of spontaneous hybridization between an exotic species Pinus mugo and the native/local P. sylvestris at the seaside spit of Kursiu Nerija in Lithuania. The objective was to identify spontaneous hybrids between P. mugo and P. sylvestris based on morphology traits among the individuals naturally regenerating at the seaside spit. The field inventory was carried out over the entire Lithuanian part of the spit, and 200 individuals morphologically intermediate between P. sylvestris and P. mugo were identified. Based on a weighted trait index, the intermediate individuals were grouped into two groups, one morphologically close to P. sylvestris and another close to P. mugo. The needle micromorphological traits of the putative hybrids were of intermediate values between P. mugo and P. sylvestris. The results provide a strong evidence of spontaneous hybridization between P. mugo and P. sylvestris in Lithuanian seaside spit of Kursiu Nerija.

  7. Grooming behavior of spontaneously hypertensive rats

    NARCIS (Netherlands)

    Buuse, M. van den; Jong, Wybren de

    1987-01-01

    In an open field spontaneously hypertensive rats (SHR) exhibited lower scores for grooming when compared to their normotensive controls, the Wistar Kyoto rats (WKY). After i.c.v. injection of 1 μg ACTH1–24 cumulative 50-min grooming scores were lower in SHR. Analysis of subscores indicated that the

  8. Spontaneous conversion of first onset atrial fibrillation

    DEFF Research Database (Denmark)

    Lindberg, Søren Østergaard; Hansen, Sidsel; Nielsen, Tonny

    2011-01-01

    Background  We studied all patients admitted to hospital with first onset atrial fibrillation (AF) to determine the probability of spontaneous conversion to sinus rhythm and to identify factors predictive of such a conversion. Methods and Results  We retrospectively reviewed charts of 438...

  9. A Fatal Complication of Dermatomyositis: Spontaneous Pneumomediastinum

    Directory of Open Access Journals (Sweden)

    Ezgi Demirdöğen Çetinoğlu

    2016-04-01

    Full Text Available Interstitial lung disease (ILD is a negative prognostic factor associated with increased morbidity and mortality in patients with dermatomyositis (DM. Spontaneous pneumomediastinum is a rare complication of DM and it can be fatal. We present a 48-year-old woman with DM and ILD complicated by pneumomediastinum without pneumothorax and subcutaneous emphysema.

  10. Spontaneous Sourcing among Students Reading Multiple Documents

    Science.gov (United States)

    Stromso, Helge I.; Braten, Ivar; Britt, M. Anne; Ferguson, Leila E.

    2013-01-01

    This study used think-aloud methodology to explore undergraduates' spontaneous attention to and use of source information while reading six documents that presented conflicting views on a controversial social scientific issue in a Google-like environment. Results showed that students explicitly and implicitly paid attention to sources of documents…

  11. Spontaneous Type 2 Diabetic Rodent Models

    Science.gov (United States)

    Wang, Yang-wei; Sun, Guang-dong; Sun, Jing; Liu, Shu-jun; Wang, Ji; Xu, Xiao-hong; Miao, Li-ning

    2013-01-01

    Diabetes mellitus, especially type 2 diabetes (T2DM), is one of the most common chronic diseases and continues to increase in numbers with large proportion of health care budget being used. Many animal models have been established in order to investigate the mechanisms and pathophysiologic progress of T2DM and find effective treatments for its complications. On the basis of their strains, features, advantages, and disadvantages, various types of animal models of T2DM can be divided into spontaneously diabetic models, artificially induced diabetic models, and transgenic/knockout diabetic models. Among these models, the spontaneous rodent models are used more frequently because many of them can closely describe the characteristic features of T2DM, especially obesity and insulin resistance. In this paper, we aim to investigate the current available spontaneous rodent models for T2DM with regard to their characteristic features, advantages, and disadvantages, and especially to describe appropriate selection and usefulness of different spontaneous rodent models in testing of various new antidiabetic drugs for the treatment of type 2 diabetes. PMID:23671868

  12. Silicon photonic crystals and spontaneous emission

    NARCIS (Netherlands)

    Dood, Michiel Jacob Andries de

    2002-01-01

    Photonic crystals, i.e. materials that have a periodic variation in refractive index, form an interesting new class of materials that can be used to modify spontaneous emission and manipulate optical modes in ways that were impossible so far. This thesis is divided in three parts. Part I discusses

  13. Association between Nutritional Status with Spontaneous Abortion

    Directory of Open Access Journals (Sweden)

    Rahimeh Ahmadi

    2016-11-01

    Full Text Available Background: Spontaneous abortion is the most common adverse pregnancy outcome. We aimed to investigate a possible link between nutrient deficiencies and the risk of spontaneous abortion. Materials and Methods: This case-control study included the case group (n=331 experiencing a spontaneous abortion before 14 weeks of pregnancy and the control group (n=331 who were healthy pregnant women over 14 weeks of pregnancy. The participants filled out Food Frequency Questionnaire (FFQ, in which they reported their frequency of consumption for a given serving of each food item during the past three months, on a daily, weekly or monthly basis. The reported frequency for each food item was converted to a daily intake. Then, consumption of nutrients was compared between the two groups. Results: There are significant differences between the two groups regarding consumed servings/day of vegetables, bread and cereal, meat, poultry, fish, eggs, beans, fats, oils and dairy products (P=0.012, P<0.001, P=0.004, P<0.001, P=0.019, respectively. There are significant differences between the two groups in all micronutrient including folic acid, iron, vitamin C, vitamin B6, vitamin B12 and zinc (P<0.001. Conclusion: Poor nutrientions may be correlated with increased risk of spontaneous abortion

  14. SPONTANEOUS CP VIOLATION AND QUARK MASS AMBIGUITIES.

    Energy Technology Data Exchange (ETDEWEB)

    CREUTZ,M.

    2004-09-21

    I explore the regions of quark masses where CP will be spontaneously broken in the strong interactions. The boundaries of these regions are controlled by the chiral anomaly, which manifests itself in ambiguities in the definition of non-degenerate quark masses. In particular, the concept of a single massless quark is ill defined.

  15. Spontaneous intracranial hypotension with slit ventricles.

    OpenAIRE

    Murros, K; Fogelholm, R

    1983-01-01

    A case of spontaneous intracranial hypotension syndrome is described. Computed tomography showed slit ventricles with tight basal cisterns. Prompt improvement of symptoms was achieved by intramuscular dexamethasone treatment. A follow-up CT scan demonstrated re-expansion of ventricles and basal cisterns.

  16. Proteomic Biomarkers for Spontaneous Preterm Birth

    DEFF Research Database (Denmark)

    Kacerovsky, Marian; Lenco, Juraj; Musilova, Ivana

    2014-01-01

    This review aimed to identify, synthesize, and analyze the findings of studies on proteomic biomarkers for spontaneous preterm birth (PTB). Three electronic databases (Medline, Embase, and Scopus) were searched for studies in any language reporting the use of proteomic biomarkers for PTB published...

  17. A gravity term from spontaneous symmetry breaking

    CERN Document Server

    Moise, Mihai

    2014-01-01

    In this model, the gravity term in the Lagrangean comes from spontaneous symmetry breaking of an additional scalar quadruplet field $\\Upsilon$. The resulting gravitational field is approximate to one of the models of coframe gravity with parameters $\\rho_1 + 4 \\rho_2 = 0$, $\\rho_3 = 0$. This article includes an exact solution of coframe gravity with model parameters $\\rho_1 \

  18. [Spontaneous perirenal urinoma during nephritic colic].

    Science.gov (United States)

    Nouira, Y; Ben Younes, A; Rekik, H; Horchani, A

    2000-06-01

    A case has been reported of the spontaneous rupture of the kidney during an attack of nephritic colic. This rare complication is due to excessive pressure in the renal cavities caused by an obstructive ureteral calculus. Complete resolution of the urinoma was obtained after endoscopic fragmentation of the calculus and double J stenting.

  19. PERIODIC-SOLUTIONS IN SPONTANEOUSLY BROKEN THEORIES

    NARCIS (Netherlands)

    BRIHAYE, Y; KUNZ, J

    1992-01-01

    A class of spontaneously broken field theories is proposed, and the occurrence of their periodic, classical solutions is investigated in detail. The emergence of multiple solutions is observed, their normal modes of oscillation are studied, and the bifurcations of the classical energy functional are

  20. Hovedpine kan skyldes spontan intrakranial hypotension

    DEFF Research Database (Denmark)

    Hansen, Lasse Berg; Bjarkam, Carsten Reidies

    2014-01-01

    Spontaneous intracranial hypotension (SIH) is an uncommon condition associated with postural headache, nausea and dizziness. It is believed to be secondary to a dural tear with resultant cerebrospinal fluid (CSF) leak. This is a case report of a pregnant woman (gestational age 31 weeks) who...

  1. Spoken Content Retrieval: Searching Spontaneous Conversational Speech

    NARCIS (Netherlands)

    Kohler, J; Larson, M; de Jong, Franciska M.G.; Ordelman, Roeland J.F.; Kraaij, W.

    2008-01-01

    The second workshop on Searching Spontaneous Conversational Speech (SSCS 2008) was held in Singapore on July 24, 2008 in conjunction with the 31st Annual International ACM SIGIR Conference. The goal of the workshop was to bring the speech community and the information retrieval community together.

  2. A Fatal Complication of Dermatomyositis: Spontaneous Pneumomediastinum

    OpenAIRE

    Ezgi Demirdöğen Çetinoğlu; Ediz Dalkılıç; Muharrem Erol; Nilüfer Aylin Acet; Ahmet Ursavaş; Ercüment Ege

    2016-01-01

    Interstitial lung disease (ILD) is a negative prognostic factor associated with increased morbidity and mortality in patients with dermatomyositis (DM). Spontaneous pneumomediastinum is a rare complication of DM and it can be fatal. We present a 48-year-old woman with DM and ILD complicated by pneumomediastinum without pneumothorax and subcutaneous emphysema.

  3. Spontaneous emission from active dielectric microstructures

    DEFF Research Database (Denmark)

    Søndergaard, Thomas; Tromborg, Bjarne

    2001-01-01

    and engineered due to the dependence of the emission rate on the location and polarisation of the emitters in the structure. This paper addresses the methods of quantum electrodynamics of dielectric media which enable calculation of the local rate of spontaneous emission in active microstructures....

  4. Spontaneous expulsion of schwannoma of epiglottis

    OpenAIRE

    1997-01-01

    A rare case of spontaneous expulsion of schwannoma of epiglottis is being reported. These are neurogenic tumours arising from the schwan sheath of peripheral, cranial and sympathetic nerves. The great majority of these neurogenic tumours originate from aryepiglottic fold or false vocal cords. However the neurofibroma of the epiglottis are quite uncommon.

  5. Spontaneous Resolution of Direct Carotid Cavernous Fistula

    NARCIS (Netherlands)

    Ishaq, Mazhar; Arain, Muhammad Aamir; Ahmed, Saadullah; Niazi, Muhammad Khizar; Khan, Muhammad Dawood; Iqbal, Zamir

    2010-01-01

    Proptosis due to carotid cavernous fistula is rare sequelae of head injury. We report a case of post-traumatic, direct high flow carotid cavernous fistula that resolved spontaneously 06 weeks after carotid angiography. It however, resulted in loss of vision due to delay in early treatment. In the ca

  6. Spontaneous abdominal wall endometriosis: a case report.

    Science.gov (United States)

    Papavramidis, Th S; Sapalidis, K; Michalopoulos, N; Karayanopoulou, G; Raptou, G; Tzioufa, V; Kesisoglou, I; Papavramidis, S T

    2009-01-01

    Endometriosis is the presence of endometrial glands and stroma outside the uterus. Spontaneous abdominal wall endometriosis (AWE) is any ectopic endometrium found superficial to the peritoneum without the presence of any previous scar. Rarely, endometriosis represents a disease of specific interest to the general surgeon, on account of its extrapelvic localisations. We describe a case with spontaneous AWE presenting as a painful mass with cyclic symptoms. A 28-year-old woman presented to the day-surgery division of our department, suffering from a painful mass in the left lower abdominal quadrant. A mobile mass of 5 x 4 cm was identified. The initial diagnosis was lipoma and excision was planned. During the operation two masses were spotted, very close to one another, and were excised within healthy limits. Pathology revealed endometrial glands surrounded by a disintegrating mantle of endometrial stroma and fibrous scar tissue in which there was a scattering of leucocytes. The woman had no scars. She was discharged from hospital after 2 hours. Two years after the excision she is free of disease and no recurrence has been observed. Spontaneous AWE is rare, accounting for 20% of all AWEs. The triad ; mass, pain and cyclic symptomatology helps in the diagnosis, but unfortunately it is not present in all cases. Spontaneous endometriomas are usually diagnosed by pathology and the treatment of choice is surgical excision.

  7. Spontaneous extracranial decompression of epidural hematoma

    Energy Technology Data Exchange (ETDEWEB)

    Neely, John C. [Marshall University School of Medicine, Huntington, WV (United States); Jones, Blaise V. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Crone, Kerry R. [Cincinnati Children' s Hospital Medical Center, Division of Neurosurgery, Cincinnati, OH (United States)

    2008-03-15

    Epidural hematoma (EDH) is a common sequela of head trauma in children. An increasing number are managed nonsurgically, with close clinical and imaging observation. We report the case of a traumatic EDH that spontaneously decompressed into the subgaleal space, demonstrated on serial CT scans that showed resolution of the EDH and concurrent enlargement of the subgaleal hematoma. (orig.)

  8. Spontaneous hedonic reactions to social media cues

    NARCIS (Netherlands)

    Koningsbruggen, G.M. van; Hartmann, T.; Eden, A.; Veling, H.P.

    2017-01-01

    Why is it so difficult to resist the desire to use social media? One possibility is that frequent social media users possess strong and spontaneous hedonic reactions to social media cues, which, in turn, makes it difficult to resist social media temptations. In two studies (total N = 200), we

  9. Spontaneous Hedonic Reactions to Social Media Cues.

    Science.gov (United States)

    van Koningsbruggen, Guido M; Hartmann, Tilo; Eden, Allison; Veling, Harm

    2017-05-01

    Why is it so difficult to resist the desire to use social media? One possibility is that frequent social media users possess strong and spontaneous hedonic reactions to social media cues, which, in turn, makes it difficult to resist social media temptations. In two studies (total N = 200), we investigated less-frequent and frequent social media users' spontaneous hedonic reactions to social media cues using the Affect Misattribution Procedure-an implicit measure of affective reactions. Results demonstrated that frequent social media users showed more favorable affective reactions in response to social media (vs. control) cues, whereas less-frequent social media users' affective reactions did not differ between social media and control cues (Studies 1 and 2). Moreover, the spontaneous hedonic reactions to social media (vs. control) cues were related to self-reported cravings to use social media and partially accounted for the link between social media use and social media cravings (Study 2). These findings suggest that frequent social media users' spontaneous hedonic reactions in response to social media cues might contribute to their difficulties in resisting desires to use social media.

  10. Spontaneous hedonic reactions to social media cues

    NARCIS (Netherlands)

    Koningsbruggen, G.M. van; Hartmann, T.; Eden, A.; Veling, H.P.

    2017-01-01

    Why is it so difficult to resist the desire to use social media? One possibility is that frequent social media users possess strong and spontaneous hedonic reactions to social media cues, which, in turn, makes it difficult to resist social media temptations. In two studies (total N = 200), we invest

  11. Neuronal avalanches in spontaneous activity in vivo.

    Science.gov (United States)

    Hahn, Gerald; Petermann, Thomas; Havenith, Martha N; Yu, Shan; Singer, Wolf; Plenz, Dietmar; Nikolic, Danko

    2010-12-01

    Many complex systems give rise to events that are clustered in space and time, thereby establishing a correlation structure that is governed by power law statistics. In the cortex, such clusters of activity, called "neuronal avalanches," were recently found in local field potentials (LFPs) of spontaneous activity in acute cortex slices, slice cultures, the developing cortex of the anesthetized rat, and premotor and motor cortex of awake monkeys. At present, it is unclear whether neuronal avalanches also exist in the spontaneous LFPs and spike activity in vivo in sensory areas of the mature brain. To address this question, we recorded spontaneous LFPs and extracellular spiking activity with multiple 4 × 4 microelectrode arrays (Michigan Probes) in area 17 of adult cats under anesthesia. A cluster of events was defined as a consecutive sequence of time bins Δt (1-32 ms), each containing at least one LFP event or spike anywhere on the array. LFP cluster sizes consistently distributed according to a power law with a slope largely above -1.5. In two thirds of the corresponding experiments, spike clusters also displayed a power law that displayed a slightly steeper slope of -1.8 and was destroyed by subsampling operations. The power law in spike clusters was accompanied with stronger temporal correlations between spiking activities of neurons that spanned longer time periods compared with spike clusters lacking power law statistics. The results suggest that spontaneous activity of the visual cortex under anesthesia has the properties of neuronal avalanches.

  12. Spoken Content Retrieval: Searching Spontaneous Conversational Speech

    NARCIS (Netherlands)

    Kohler, J; Larson, M; Jong, de F.M.G.; Kraaij, W.; Ordelman, R.J.F.

    2008-01-01

    The second workshop on Searching Spontaneous Conversational Speech (SSCS 2008) was held in Singapore on July 24, 2008 in conjunction with the 31st Annual International ACM SIGIR Conference. The goal of the workshop was to bring the speech community and the information retrieval community together. T

  13. Surgical management of spontaneous ruptured hepatocellular adenoma

    Directory of Open Access Journals (Sweden)

    Marcelo Augusto Fontenelle Ribeiro Junior

    2009-01-01

    Full Text Available AIMS: Spontaneous ruptured hepatocellular adenoma (SRHA is a rare life-threatening condition that may require surgical treatment to control hemorrhaging and also stabilize the patient. We report a series of emergency surgeries performed at our institution for this condition. METHODS: We reviewed medical records and radiology files of 28 patients (from 1989 to 2006 with a proven diagnosis of hepatocellular adenoma (HA. Three (10.7% of 28 patients had spontaneous ruptured hepatocellular adenoma, two of which were associated with intrahepatic hemorrhage while one had intraperitoneal bleeding. Two patients were female and one was male. Both female patients had a background history of oral contraceptive use. Sudden abdominal pain associated with hemodynamic instability occurred in all patients who suffered from spontaneous ruptured hepatocellular adenoma. The mean age was 41.6 years old. The preoperative assessment included liver function tests, ultrasonography and computed tomography. RESULTS: The surgical approaches were as follows: right hemihepatectomy for controlling intraperitoneal bleeding, and right extended hepatectomy and non-anatomic resection of the liver for intrahepatic hemorrhage. There were no deaths, and the postoperative complications were bile leakage and wound infection (re-operation, as well as intraperitoneal abscess (re-operation and pleural effusion. CONCLUSION: Spontaneous ruptured hepatocellular adenoma may be treated by surgery for controlling hemorrhages and stabilizing the patient, and the decision to operate depends upon both the patient's condition and the expertise of the surgical team.

  14. Polk Mutant Mice Have a Spontaneous Mutator Phenotype

    Science.gov (United States)

    Stancel, J. Nicole Kosarek; McDaniel, Lisa D.; Velasco, Susana; Richardson, James; Guo, Caixia; Friedberg, Errol C.

    2009-01-01

    Mice defective in the Polk gene (which encodes DNA polymerase kappa) are viable and do not manifest obvious phenotypes. The present studies document a spontaneous mutator phenotype in Polk−/− mice. The initial indication of enhanced spontaneous mutations in these mice came from the serendipitous observation of a postulated founder mutation that manifested in multiple disease states among a cohort of mice comprising all three possible Polk genotypes. Polk−/− and isogenic wild type controls carrying a reporter transgene (the λ-phage cII gene) were used for subsequent quantitative and qualitative studies on mutagenesis in various tissues. We observed significantly increased mutation frequencies in the kidney, liver, and lung of Polk−/− mice, but not in the spleen or testis. G:C base pairs dominated the mutation spectra of the kidney, liver, and lung. These results are consistent with the notion that Polκ is required for accurate translesion DNA synthesis past naturally occurring polycyclic guanine adducts, possibly generated by cholesterol and/or its metabolites. PMID:19783230

  15. Spontaneous gastric carcinomas in sooty mangabeys (Cercocebus atys).

    Science.gov (United States)

    Sharma, Prachi; Cohen, Joyce K; Paul, Katherine S; Courtney, Cynthia L; Johnson, Zachary P; Anderson, Daniel C

    2011-12-01

    Sooty mangabeys (Cercocebus atys) are native to West Africa and are a natural host of SIV, which is implicated in the origin of HIV2. They have been used in studies of AIDS pathogenesis, leprosy, immune responses, reproductive biology, and behavior. Spontaneous tumors have rarely been reported in this species. However, we noted spontaneous gastric carcinomas in 8 sooty mangabeys. Four male and 4 female mangabeys had mild to severe chronic weight loss, with abdominal distention in 5 of 8 animals. At necropsy, 7 of the 8 mangabeys had prominent large ulcerated masses with severe, diffuse thickening of the pyloric wall at or near the gastric-duodenal junction, which often partially occluded the gastric lumen. Early carcinoma was an incidental finding in one mangabey. Histologically, all of the tumors were classified as adenocarcinomas. Adenocarcinomas were noncircumscribed with infiltrates of neoplastic epithelial cells, often arranged in acini. In 3 mangabeys, these infiltrates were transmural and invaded surrounding tissue locally. The adenocarcinomas were locally invasive, with metastasis to regional lymph nodes in 2 animals, but widespread metastasis was not seen. Anisocytosis, anisokaryosis, and high mitotic rates were seen in all 8 tumors. In the samples available, serology and Steiner stain did not detect Helicobacter, and immunohistochemistry failed to reveal Helicobacter or Epstein-Barr virus, 2 potential causes for human gastric carcinomas.

  16. Spontaneous Atherosclerosis in Free-Living Pigeons in Mosul Area, Iraq

    Directory of Open Access Journals (Sweden)

    Hahfidh I. Al-Sadi* and Ashraf K. Abdullah

    2011-04-01

    Full Text Available The purpose of this study was to investigate for the first time the prevalence and pathology of spontaneous atherosclerosis in free – living pigeons in Mosul, Iraq. A hundred apparently healthy, 1-1.5 year old both sex pigeons of local breed free – living used. Effects of factors such as weight, sex, age and health status on prevalence of the condition were also studied. Prevalence of naturally occurring atherosclerosis was 10%. Grossly, the heart was hypertrophied and of firm consistency, aorta and coronary arteries were prominent and cordlike with thickened walls. Microscopically, lipid – laden "foam cells" were seen throughout the thickened tunica media and intima. Damage of the elastic lamellae and hypertrophy of the smooth muscle cells were also noted. Spontaneous atherosclerosis occurred more frequently in old pigeons. No effect was found for sex, weight, and health status of the pigeons on prevalence and pathology of spontaneous atherosclerosis. It was concluded that spontaneous atherosclerosis is fairly common in local pigeons and it occurred more commonly in old pigeons. Sex, weight, and health status of the pigeons did not constitute risk factors for the occurrence of spontaneous atherosclerosis.

  17. Spontaneous sensorimotor coupling with multipart music.

    Science.gov (United States)

    Hurley, Brian K; Martens, Peter A; Janata, Petr

    2014-08-01

    Music often evokes spontaneous movements in listeners that are synchronized with the music, a phenomenon that has been characterized as being in "the groove." However, the musical factors that contribute to listeners' initiation of stimulus-coupled action remain unclear. Evidence suggests that newly appearing objects in auditory scenes orient listeners' attention, and that in multipart music, newly appearing instrument or voice parts can engage listeners' attention and elicit arousal. We posit that attentional engagement with music can influence listeners' spontaneous stimulus-coupled movement. Here, 2 experiments-involving participants with and without musical training-tested the effect of staggering instrument entrances across time and varying the number of concurrent instrument parts within novel multipart music on listeners' engagement with the music, as assessed by spontaneous sensorimotor behavior and self-reports. Experiment 1 assessed listeners' moment-to-moment ratings of perceived groove, and Experiment 2 examined their spontaneous tapping and head movements. We found that, for both musically trained and untrained participants, music with more instruments led to higher ratings of perceived groove, and that music with staggered instrument entrances elicited both increased sensorimotor coupling and increased reports of perceived groove. Although untrained participants were more likely to rate music as higher in groove, trained participants showed greater propensity for tapping along, and they did so more accurately. The quality of synchronization of head movements with the music, however, did not differ as a function of training. Our results shed new light on the relationship between complex musical scenes, attention, and spontaneous sensorimotor behavior.

  18. The spontaneous formation of stereotypes via cumulative cultural evolution.

    Science.gov (United States)

    Martin, Douglas; Hutchison, Jacqui; Slessor, Gillian; Urquhart, James; Cunningham, Sheila J; Smith, Kenny

    2014-09-01

    All people share knowledge of cultural stereotypes of social groups--but what are the origins of these stereotypes? We examined whether stereotypes form spontaneously as information is repeatedly passed from person to person. As information about novel social targets was passed down a chain of individuals, what initially began as a set of random associations evolved into a system that was simplified and categorically structured. Over time, novel stereotypes emerged that not only were increasingly learnable but also allowed generalizations to be made about previously unseen social targets. By illuminating how cognitive and social factors influence how stereotypes form and change, these findings show how stereotypes might naturally evolve or be manipulated. © The Author(s) 2014.

  19. Brief, embedded, spontaneous metacognitive talk indicates thinking like a physicist

    CERN Document Server

    Sayre, Eleanor C

    2014-01-01

    Instructors and researchers think "thinking like a physicist" is important for students' professional development. However, precise definitions and observational markers remain elusive. We reinterpret popular beliefs inventories in physics to indicate what physicists think "thinking like a physicist" entails. Through discourse analysis of upper-division students' speech in natural settings, we show that students may appropriate or resist these elements. We identify a new element in the physicist speech genre: brief, embedded, spontaneous metacognitive talk (BESM talk). BESM talk communicates students' in-the-moment enacted expectations about physics as a technical field and a cultural endeavor. Students use BESM talk to position themselves as physicists or non-physicists. Students also use BESM talk to communicate their expectations in four ways: understanding, confusion, spotting inconsistencies, and generalized expectations.

  20. Spontaneous spiking in an autaptic Hodgkin-Huxley set up

    CERN Document Server

    Li, Yunyun; Hanggi, Peter; Schimansky-Geier, Lutz

    2010-01-01

    The effect of intrinsic channel noise is investigated for the dynamic response of a neuronal cell with a delayed feedback loop. The loop is based on the so-called autapse phenomenon in which dendrites establish not only connections to neighboring cells but as well to its own axon. The biophysical modeling is achieved in terms of a stochastic Hodgkin-Huxley model containing such a built in delayed feedback. The fluctuations stem from intrinsic channel noise, being caused by the stochastic nature of the gating dynamics of ion channels. The influence of the delayed stimulus is systematically analyzed with respect to the coupling parameter and the delay time in terms of the interspike interval histograms and the average interspike interval. The delayed feedback manifests itself in the occurrence of bursting and a rich multimodal interspike interval distribution, exhibiting a delay-induced reduction of the spontaneous spiking activity at characteristic frequencies. Moreover, a specific frequency-locking mechanism ...

  1. Spontaneous Transition of Turbulent Flames to Detonations in Unconfined Media

    CERN Document Server

    Poludnenko, Alexei Y; Oran, Elaine S

    2011-01-01

    Deflagration-to-detonation transition (DDT) can occur in environments ranging from experimental and industrial systems to astrophysical thermonuclear (type Ia) supernovae explosions. Substantial progress has been made in explaining the nature of DDT in confined systems with walls, internal obstacles, or pre-existing shocks. It remains unclear, however, whether DDT can occur in unconfined media. Here we use direct numerical simulations (DNS) to show that for high enough turbulent intensities unconfined, subsonic, premixed, turbulent flames are inherently unstable to DDT. The associated mechanism, based on the nonsteady evolution of flames faster than the Chapman-Jouguet deflagrations, is qualitatively different from the traditionally suggested spontaneous reaction wave model, and thus does not require the formation of distributed flames. Critical turbulent flame speeds, predicted by this mechanism for the onset of DDT, are in agreement with DNS results.

  2. Controlling spontaneous emission of light by photonic crystals

    DEFF Research Database (Denmark)

    Lodahl, Peter

    2005-01-01

    Photonic bandgap crystals were proposed almost two decades ago as a unique tool for controlling propagation and emission of light. Since then the research field of photonic crystals has exploded and many beautiful demonstrations of the use of photonic crystals and fibers for molding light...... propagation have appeared that hold great promises for integrated optics. These major achievements solidly demonstrate the ability to control propagation of light. In contrast, an experimental demonstration of the use of photonic crystals for timing the emission of light has so far lacked. In a recent...... publication in Nature, we have demonstrated experimentally that both the direction and time of spontaneous emission can be controlled, thereby confirming the original proposal by Eli Yablonovich that founded the field of photonic crystals. We believe that this work opens new opportunities for solid...

  3. Brief, embedded, spontaneous metacognitive talk indicates thinking like a physicist

    Science.gov (United States)

    Sayre, Eleanor C.; Irving, Paul W.

    2015-12-01

    [This paper is part of the Focused Collection on Upper Division Physics Courses.] Instructors and researchers think "thinking like a physicist" is important for students' professional development. However, precise definitions and observational markers remain elusive. We reinterpret popular beliefs inventories in physics to indicate what physicists think thinking like a physicist entails. Through discourse analysis of upper-division students' speech in natural settings, we show that students may appropriate or resist these elements. We identify a new element in the physicist speech genre: brief, embedded, spontaneous metacognitive talk (BESM talk). BESM talk communicates students' in-the-moment enacted expectations about physics as a technical field and a cultural endeavor. Students use BESM talk to position themselves as physicists or nonphysicists. Students also use BESM talk to communicate their expectations in four ways: understanding, confusion, spotting inconsistencies, and generalized expectations.

  4. Spontaneous breakdown of local conformal invariance in quantum gravity

    CERN Document Server

    't Hooft, Gerard

    2015-01-01

    This chapter shows how the black hole complementarity principle can be naturally implemented by treating local conformal invariance as an exact but spontaneously broken symmetry of quantum gravity. This allows a description of the black hole either in terms of the imploding particles or entirely in terms of the emerging Hawking particles. These complementary representations can be obtained from one another by a local conformal transformation; this implies that the black hole scattering matrix is equivalent to a local conformal gauge transformation. Perturbative canonical quantum gravity, coupled to a renormalizable model for matter fields, has this conformal symmetry built in, and this symmetry would be exact if the local conformal anomalies cancelled. The Einstein–Hilbert action can be regarded as breaking local conformal invariance only dynamically, not explicitly. The functional integral over the dilaton component of the metric field can be disentangled from the other integrations over the metric and the...

  5. Randomness generation based on spontaneous emissions of lasers

    Science.gov (United States)

    Zhou, Hongyi; Yuan, Xiao; Ma, Xiongfeng

    2015-06-01

    Random numbers play a key role in information science, especially in cryptography. Based on the probabilistic nature of quantum mechanics, quantum random number generators can produce genuine randomness. In particular, random numbers can be produced from laser phase fluctuations with a very high speed, typically in the Gbps regime. In this work, by developing a physical model, we investigate the origin of the randomness in quantum random number generators based on laser phase fluctuations. We show how the randomness essentially stems from spontaneous emissions. The laser phase fluctuation can be quantitatively evaluated from basic principles and qualitatively explained by the Brownian motion model. After taking account of practical device precision, we show that the randomness generation speed is limited by the finite resolution of detection devices. Our result also provides the optimal experiment design in order to achieve the maximum generation speed.

  6. Spontaneous Perinephric Hemorrhage Associated with Urolithiasis in Pregnancy

    Directory of Open Access Journals (Sweden)

    Leah P. McMann

    2004-01-01

    Full Text Available Spontaneous perinephric hematoma in the absence of anticoagulation, arteritis, or trauma is uncommon. We report the case of a postpartum patient with nephrolithiasis who initially presented to the obstetric service with a spontaneous perinephric hemorrhage.

  7. Spontaneous perinephric hemorrhage associated with urolithiasis in pregnancy.

    Science.gov (United States)

    McMann, Leah P; Peterson, Andrew C; Ahuja, Sunil A

    2004-06-07

    Spontaneous perinephric hematoma in the absence of anticoagulation, arteritis, or trauma is uncommon. We report the case of a postpartum patient with nephrolithiasis who initially presented to the obstetric service with a spontaneous perinephric hemorrhage.

  8. Spontaneous Perinephric Hemorrhage Associated with Urolithiasis in Pregnancy

    OpenAIRE

    2004-01-01

    Spontaneous perinephric hematoma in the absence of anticoagulation, arteritis, or trauma is uncommon. We report the case of a postpartum patient with nephrolithiasis who initially presented to the obstetric service with a spontaneous perinephric hemorrhage.

  9. Socioeconomic position and the risk of spontaneous abortion

    DEFF Research Database (Denmark)

    Norsker, Filippa Nyboe; Espenhain, Laura; A Rogvi, Sofie

    2012-01-01

    To investigate the relationship between different indicators of socioeconomic position and the risk of spontaneous abortion.......To investigate the relationship between different indicators of socioeconomic position and the risk of spontaneous abortion....

  10. [Bacterial vaginosis and spontaneous preterm birth].

    Science.gov (United States)

    Brabant, G

    2016-12-01

    To determine if bacterial vaginosis is a marker for risk of spontaneous preterm delivery and if its detection and treatment can reduce this risk. Consultation of the database Pubmed/Medline, Science Direct, and international guidelines of medical societies. Bacterial vaginosis (BV) is a dysbiosis resulting in an imbalance in the vaginal flora through the multiplication of anaerobic bacteria and jointly of a disappearance of well-known protective Lactobacilli. His diagnosis is based on clinical Amsel criteria and/or a Gram stain with establishment of the Nugent score. The prevalence of the BV extraordinarily varies according to ethnic and/or geographical origin (4-58 %), in France, it is close to 7 % in the first trimester of pregnancy (EL2). The link between BV and spontaneous premature delivery is low with an odds ratio between 1.5 and 2 in the most recent studies (EL3). Metronidazole or clindamycin is effective to treat BV (EL3). It is recommended to prescribe one of these antibiotics in the case of symptomatic BV (Professional Consensus). The testing associated with the treatment of BV in the global population showed no benefit in the prevention of the risk of spontaneous preterm delivery (EL2). Concerning low-risk asymptomatic population (defined by the absence of antecedent of premature delivery), it has been failed profit to track and treat the BV in the prevention of the risk of spontaneous preterm delivery (EL1). Concerning the high-risk population (defined by a history of preterm delivery), it has been failed profit to track and treat the VB in the prevention of the risk of spontaneous preterm delivery (EL3). However, in the sub population of patients with a history of preterm delivery occurred in a context of materno-fetal bacterial infection, there may be a benefit to detect and treat early and systematically genital infection, and in particular the BV (Professional Consensus). The screening and treatment of BV during pregnancy in asymptomatic low

  11. Analysis of the Spontaneous Abortion in Chinese Married Women

    Institute of Scientific and Technical Information of China (English)

    高尔生; 邓新清; 何更生; 方可娟; 唐威; 楼超华

    1994-01-01

    The spontaneous abortion is a common type of pregnant outcomes. The spontaneous abortion rate can be used to indicate the women's fecundity and the level of the reproductive health. It is also a sensitive indicator for determing the social, economic, and health status and prenatal care. To explore the preventive method for spontaneous abortion and improve women's health level, it is important to evaluate the status of spontaneous abortion and to determine the factors affecting

  12. F. VON HAYEK’S THEORY OF SPONTANEOUS ORDER

    Directory of Open Access Journals (Sweden)

    О. Nesterenko

    2013-04-01

    Full Text Available The essence and the genesis of spontaneous order are disclosed in the context of critical analysis of constructivism. The author’s approach to the definition of the characteristic features of the spontaneous order is proposed. The dichotomy of the order is revealed towards the economic sphere in form of spontaneous order and organization.

  13. [Complications in the therapy of spontaneous pneumothorax].

    Science.gov (United States)

    Eggeling, S

    2015-05-01

    The therapy of spontaneous pneumothorax is a common necessity in hospitals of all care hierarchies In addition to sufficient primary treatment by placement of a thorax drainage, knowledge of complicationg constellations, recognition of complications and irregular courses during the therapy of spontaneous pneumothorax are of fundamental importance for achieving a satisfactory treatment outcome. Furthermore, the enlightenment of patients regarding the pathogenesis of the disease, possible measures for influencing the recurrence rate and information about future behavioral and lifestyle modifications are important. The principal complications during hospital treatment can be subdivided into complications of the surgical placement of the thorax drain and relief of the pleural cavity, problems in the management of treatment of the pleural negative pressure, the possibly demanding management of a persisting air leak and the individualized decision-making with respect to an interventional or operative procedure. The most common complicating constellations and possible complications during the inpatient hospital stay are described, the.

  14. Laboratory observations of spontaneous magnetic reconnection.

    Science.gov (United States)

    Egedal, J; Fox, W; Katz, N; Porkolab, M; Reim, K; Zhang, E

    2007-01-05

    Detailed measurements of spontaneous magnetic reconnection are presented. The experimental data, which were obtained in the new closed Versatile Toroidal Facility magnetic configuration, document the profile evolution of the plasma density, magnetic flux function, reconnection rate, and the current density during a spontaneous reconnection event in the presence of a strong guide magnetic field. The reconnection process is at first slow, which allows magnetic stress to build in the system while the current channel becomes increasingly narrow and intense. The onset of a fast reconnection event occurs as the width of the current channel approaches the ion-sound-Larmor radius rho s. During the reconnection event magnetically stored energy is channeled into energetic ion outflows and a rapid increase in the electron temperature.

  15. Spontaneous synchrony in power-grid networks

    CERN Document Server

    Motter, Adilson E; Anghel, Marian; Nishikawa, Takashi

    2013-01-01

    An imperative condition for the functioning of a power-grid network is that its power generators remain synchronized. Disturbances can prompt desynchronization, which is a process that has been involved in large power outages. Here we derive a condition under which the desired synchronous state of a power grid is stable, and use this condition to identify tunable parameters of the generators that are determinants of spontaneous synchronization. Our analysis gives rise to an approach to specify parameter assignments that can enhance synchronization of any given network, which we demonstrate for a selection of both test systems and real power grids. Because our results concern spontaneous synchronization, they are relevant both for reducing dependence on conventional control devices, thus offering an additional layer of protection given that most power outages involve equipment or operational errors, and for contributing to the development of "smart grids" that can recover from failures in real time.

  16. Characteristics of spontaneous fission of 250No

    Science.gov (United States)

    Svirikhin, A. I.; Andreev, A. V.; Yeremin, A. V.; Izosimov, I. N.; Isaev, A. V.; Kuznetsov, A. N.; Kuznetsova, A. A.; Malyshev, O. N.; Popeko, A. G.; Popov, Y. A.; Sokol, E. A.; Chelnokov, M. L.; Chepigin, V. I.; Schneidman, T. M.; Gall, B.; Dorvaux, O.; Brione, P.; Hauschild, K.; Lopez-Martenz, A.; Rezynkina, K.; Mullins, S.; Jones, P.; Mosat, P.

    2017-07-01

    This study describes an experiment on investigating the properties of spontaneous fission of shortlived neutron-deficient nuclei synthesized in the reaction of complete fusion 48Ca + 204Pb = 252No*. The experiment is performed using the SHELS separator and the beam of multicharged ions at U-400 accelerator (LNR, JINR). Two activities undergoing spontaneous fission, which can be related to the ground and isomeric states of 250No nucleus, are registered. The half-lives, total kinetic energies of fission fragments, and neutron multiplicities are measured for the short-lived nuclei. The average number of neutrons per fission for the activity with t 1/2 = 5.1 ± 0.3 μs is = 4.38 ± 0.13 μs, and for nuclei with the half-life t 1/2 = 36 ± 3 μs it is xxxxx.

  17. Friction boosted by spontaneous epitaxial rotations

    Science.gov (United States)

    Mandelli, Davide; Vanossi, Andrea; Manini, Nicola; Tosatti, Erio

    2015-03-01

    It is well known in surface science that incommensurate adsorbed monolayers undergo a spontaneous, energy-lowering epitaxial rotation from aligned to misaligned relative to a periodic substrate. We show first of all that a model 2D colloidal monolayer in an optical lattice, of recent importance as a frictional model, also develops in full equilibrium a small rotation angle, easy to detect in the Moiré pattern. The colloidal monolayer misalignment is then shown by extensive sliding simulations to increase the dynamic friction by a considerable factor over the aligned case. More generally, this example suggests that spontaneous rotations are rather ubiquitous and should not be ignored in all tribological phenomena between mismatched lattices. This work was mainly supported by the ERC Advanced Grant No. 320796-MODPHYSFRICT, and partly by SINERGIA contract CRSII2 136287, by PRIN/COFIN Contract 2010LLKJBX 004, by COST Action MP1303.

  18. Spontaneous Oscillations in an Active Matter System

    Science.gov (United States)

    Hayes, Robert; Tsang, Boyce; Granick, Steve

    Active matter (which consumes energy to move about) can organize into dynamic structures more interesting than those possible at steady-state. Here we show spontaneous periodic self-assembly in a simple three-component system of water, oil phase, and surfactant at constant room temperature, with emphasis on one model system. Benchtop experiments show that liquid crystal oil droplets spontaneously and collectively oscillate like a `beating heart' for several hours; contract, relax, and subsequently re-contract in a petri dish at a rate of a few `beats' per minute. These oscillations, emergent from the cooperative interaction of the three components, are driven by the competition between positive and negative feedback processes. This illustration of feedback in action reveals a new way to program self-assembled structures to vary with time.

  19. Spontaneous Electrical Activity of Dionaea muscipula.

    Science.gov (United States)

    Balotin, N M; Dipalma, J R

    1962-12-21

    Instillation of four to six drops of 3-percent saline in the leaf trap of Dionaea muscipula Ellis causes the appearance of a series of spontaneous action potentials. Mechanical stimulation of the sensitive leaf hair elicits only a single response. Immersion in 3-percent, but not in 1-percent, saline effects a loss of weight in Dionaea but not in the leaves of gardenia or geranium.

  20. Basal body temperature recordings in spontaneous abortion.

    Science.gov (United States)

    Cohen, J; Iffy, L; Keyser, H H

    1976-01-01

    Basal body temperature (BBT) charts taken during the cycle of conception in cases that resulted in spontaneous abortion appear to provide the best available information concerning events associated with time of fertilization in doomed gestations. This study is based on a series of 227 patients who had early spontaneous abortion occurring between January 1967 and December 1974. A diagnosis of pregnancy initiated regular assays of urinary estrogen and pregnanediol excretion. Patients were instructed to report any bleeding episode which might occur, and to preserve all tissues that might be expelled. A total of 11 basal body temperature charts were obtained from patients who had subsequent early spontaneous abortion. Chromosome studies and histologic investigations were conducted. Another group of 11 consecutive BBT records were obtained from patients who had normal deliveries. The study shows that women with normal cycles experience a midcycle temperature rise requiring 1 to 3 days. In subsequent patients, this time limit was exceeded in 7 out of 11 cases of early abortion, and in 4 of 11 fertilization that resulted in an apparently normal gestation and infant. As temperature rise resulted from vigorous progesterone secretion by the corpus luteum, subnormal levels indicate inadequate steroidogenesis in the early luteal phase, and falling estrogen and progesterone levels predicted fetal demise in all cases. These findings are useful in the management of early pregnancy that follows repeated spontaneous first trimester abortions or a prolonged period of infertility. They also confirm experimental and clinical evidence regarding the role of ovulation defects in the occurrence of various types of reproductive wastage, including early abortion, anatomic and chromosome defects of the embryo and others. Prospective studies of cycles of conception through BBT recordings/hormone assays may shed light in the understanding of defects of human reproduction.

  1. Concentration-Independent Spontaneously Forming Biomimetric Vesicles

    Science.gov (United States)

    Nieh, M.-P.; Harroun, T. A.; Raghunathan, V. A.; Glinka, C. J.; Katsaras, J.

    2003-10-01

    In this Letter we present small-angle neutron scattering data from a biomimetic system composed of the phospholipids dimyristoyl and dihexanoyl phosphorylcholine (DMPC and DHPC, respectively). Doping DMPC-DHPC multilamellar vesicles with either the negatively charged lipid dimyristoyl phosphorylglycerol (DMPG, net charge -1) or the divalent cation, calcium (Ca2+), leads to the spontaneous formation of energetically stabilized monodisperse unilamellar vesicles whose radii are concentration independent and in contrast with previous experimental observations.

  2. Spontaneous Splenic Hemorrhage in the Newborn

    OpenAIRE

    2015-01-01

    Spontaneous splenic hemorrhage in the newborn is a rare entity. The presentation is usually with a triad of bleeding, abdominal distension, and hemoperitoneum. Rapid diagnosis is essential as left untreated, death is inevitable. We present a case with an unusual initial presentation of a scrotal hematocele and ultrasonography suggesting an adrenal hemorrhage. At laparotomy, splenic preservation was unsuccessful, and therefore, splenectomy was performed. The child recovered well from the proce...

  3. Short wave diathermy for small spontaneous pneumothorax

    OpenAIRE

    1997-01-01

    BACKGROUND: The treatment of small spontaneous pneumothorax can involve observation, tube thoracostomy, and surgery. This study evaluated the use of short wave diathermy as a method of accelerating the resolution of small pneumothoraces. METHODS: Twenty two patients with pneumothoraces of less than 30% by volume were randomly allocated to receive short wave diathermy for 25 minutes each day (n = 11) or observation with bed rest (n = 11). Chest radiographs were taken until the pneumothor...

  4. Spontaneous pneumomediastinum due to paralytic rabies

    Directory of Open Access Journals (Sweden)

    Wuping Wang

    2013-02-01

    Full Text Available Rabies is a fatal disease resulting from rabies virus infection, causing severe neurological symptoms and ultimately death by destroying the nervous system. In general, a patient tends to see a neurologist or an infectious diseases physician, with very common and typical discipline-related signs and symptoms, such as hydrophobia, aerophobia, and mental disorders. However, we reported a rabies patient who was first admitted to see a thoracic surgeon with spontaneous pneumomediastinum.

  5. Spontaneous bladder rupture in acute alcohol intoxication

    Directory of Open Access Journals (Sweden)

    Bahjat Barakat

    2014-03-01

    Full Text Available Spontaneous bladder rupture is a rare condition that can be followed by an acute alcohol intoxication and can be associated with significant morbidity and mortality. We report a case diagnosed in a alcoholic young male who was admitted to our emergency room for epigastric pain. The case demonstrates the difficulties with diagnosis and the need for physicians who work in an emergency room to be aware of this condition.

  6. Spontaneous resolution of a gallstone ileus.

    Science.gov (United States)

    Roberts, Ja; Lambrianides, Al

    2012-03-01

    Gallstone ileus is an uncommon complication of cholelithiasis, usually associated with an internal biliary fistula. Management of gallstone ileus is surgical with enterolithotomy the procedure of choice, followed by fistula closure either as a one or two stage procedure. In this case a 66 year old female presented with colicky abdominal pain, computed tomography (CT) clearly showing a gallstone ileus and cholecystoduodenal fistula. Despite this the patient refused surgery and went on to have spontaneous resolution of the obstruction and passage of gallstones.

  7. Spontaneous Nif- mutants of Rhodopseudomonas capsulata.

    OpenAIRE

    Wall, J D; Love, J.; Quinn, S P

    1984-01-01

    Revertible, spontaneous Nif- mutants of Rhodopseudomonas capsulata have been shown to accumulate in cultures growing photosynthetically with an amino acid as the nitrogen source such that H2 is maximally produced. The majority of such strains carry mutations which are clustered in a short region of the chromosome, probably representing one or two genes. Because this cluster includes temperature-sensitive mutations, it is also likely that it identifies the structural gene of a polypeptide. The...

  8. Urosepsis complicated by a spontaneous bladder perforation.

    Science.gov (United States)

    Lutwak, Nancy; Dill, Curt

    2011-11-08

    The authors present a case of a 72-year-old diabetic male s/p pelvic irradiation for prostate carcinoma who arrived in the emergency department with complaints of shaking chills. After admission for urosepsis, he developed severe abdominal pain and examination revealed a diffusely tender abdomen. The patient was diagnosed with spontaneous urinary bladder perforation and underwent surgery. After several weeks of intravenous antibiotics, he was discharged with multiple drains in place and bilateral nephrostomy tubes.

  9. Spontaneous bacterial peritonitis: Few additional points

    Institute of Scientific and Technical Information of China (English)

    Pankaj Jain

    2009-01-01

    Spontaneous bacterial peritonitis (SBP) is a treatable complication of decompensated cirrhosis. Coagulopathy with evidence of hyperfibrinolysis or clinically evident disseminated intravascular coagulation precludes paracentesis. Alcoholic hepatitis with fever, leucocytosis and abdominal pain should be evaluated for SBP. Oral ofloxacin is as effective as parenteral cefotaxime in treatment of SBP except for inpatients with vomiting,encephalopathy, or renal failure. Albumin is superior to hydroxyethyl starch in treatment of SBP.

  10. Spontaneous human speech mimicry by a cetacean.

    Science.gov (United States)

    Ridgway, Sam; Carder, Donald; Jeffries, Michelle; Todd, Mark

    2012-10-23

    Although dolphins (Tursiops truncatus) have been trained to match numbers and durations of human vocal bursts and reported to spontaneously match computer-generated whistles, spontaneous human voice mimicry has not previously been demonstrated. The first to study white whale (Delphinapterus leucas) sounds in the wild, Schevill and Lawrence wrote that "occasionally the calls would suggest a crowd of children shouting in the distance". Fish and Mowbary described sound types and reviewed past descriptions of sounds from this vociferous species. At Vancouver Aquarium, Canada, keepers suggested that a white whale about 15 years of age, uttered his name "Lagosi". Other utterances were not perceptible, being described as "garbled human voice, or Russian, or similar to Chinese" by R.L. Eaton in a self-published account in 1979. However, hitherto no acoustic recordings have shown how such sounds emulate speech and deviate from the usual calls of the species. We report here sound recordings and analysis which demonstrate spontaneous mimicry of the human voice, presumably a result of vocal learning, by a white whale. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Spontaneous fission of the heaviest elements

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D.C.

    1989-04-01

    Although spontaneous fission was discovered in /sup 238/U in 1940, detailed studies of the process were first made possible in the 1960's with the availability of milligram quantities of /sup 252/Cf. The advent of solid-state detectors made it possible to perform measurements of coincident fission fragments from even very short-lived spontaneous fission activities or those available in only very small quantities. Until 1971 it was believed that the main features of the mass and kinetic-energy distributions were essentially the same as those for thermal neutron-induced fission and that all low-energy fission proceeded via asymmetric mass division with total kinetic energies which could be derived by linear extrapolation from those of lighter elements. In 1971, measurements of /sup 257/Fm showed an increase in symmetric mass division with anomalously high TKE's. Subsequent experiments showed that in /sup 258/Fm and /sup 259/Fm, the most probable mass split was symmetric with very high total kinetic energy. Measurements for the heavier elements have shown symmetric mass distributions with both high and low total kinetic energies. Recent results for spontaneous fission properties of the heaviest elements are reviewed and compared with theory. 31 refs., 8 figs., 1 tab.

  12. Spontaneous retroclival hematoma: a case series.

    Science.gov (United States)

    Narvid, Jared; Amans, Matthew R; Cooke, Daniel L; Hetts, Steven W; Dillon, William P; Higashida, Randall T; Dowd, Christopher F; Halbach, Van V

    2016-03-01

    Retroclival hematomas are rare, appearing mostly as posttraumatic phenomena in children. Spontaneous retroclival hematoma (SRH) in the absence of trauma also has few descriptions in the literature. None of the reported clinical cases features the combination of an SRH and intraventricular hemorrhage (IVH). Nevertheless, despite extensive cases of idiopathic or angiographically negative subarachnoid hemorrhage (SAH) of the posterior fossa, only a single case report of a patient with a unique spontaneous retroclival hematoma has been identified. In this study, the authors reviewed the presentation, management, and clinical outcome of this rare entity. The authors performed a retrospective analysis of all patients with diagnosed SRH at their institution over a 3-year period. Collected data included clinical history, laboratory results, treatment, and review of all imaging studies performed. Four patients had SRH. All were appropriately evaluated for coagulopathic and/or traumatic etiologies of hemorrhage, though no etiology could be found. Moreover, all of the patients demonstrated SRH that both clearly crossed the basioccipital synchondrosis and was contained within a nondependent configuration along the retroclival dura mater. Spontaneous retroclival hematoma, often associated with IVH, is a rare subtype of intracranial hemorrhage frequently recognized only when MRI demonstrates compartmentalization of the posterior fossa hemorrhage. When angiography fails to reveal an underlying lesion, SRH patients, like patients with traditional angiographically negative SAH, enjoy a remarkably good prognosis.

  13. Spontaneous Healing and Treatment Alternatives in Burns

    Directory of Open Access Journals (Sweden)

    Mehmet Bozkurt

    2013-06-01

    Full Text Available Tissue losses that may occur in certain burn wounds may heal spontaneously without requiring any surgical intervention. However, this spontaneous healing is usually observed in smaller and superficial burn wounds, whereas surgical intervention may be indispensable in the tissue damages that occur in deeper and larger-scale burns treated using classical methods. Although surgery is frequently applied in the treatment of burn wounds, the variety of methods that enhance spontaneous healing are increasing in number. For this purpose, these methods involve the prevention of the wound from drying and maintaining a physiological and aseptic moisturization. On the other hand, especially in burn wounds with extensive tissue loss, the lack of adequate skin donor areas gives rise to the need for a cover material alternative to the skin. For these reasons, efforts to develop equivalent materials that may replace the original skin are progressing rapidly nowadays. The increase in the variety and advantages of the materials, which are developed using state-of-the-art bioengineering methods in the light of modern technologies, is quite promising. [Arch Clin Exp Surg 2013; 2(3.000: 186-196

  14. Spontaneous globe luxation in iatrogenic Cushing syndrome.

    Science.gov (United States)

    Ortega-Evangelio, Leticia; Navarrete-Sanchis, Javier; Williams, Basil K; Tomas-Torrent, Juan Miguel

    2015-10-01

    We report a rare case of spontaneous eyeball luxation associated with exophthalmos due to iatrogenic Cushing syndrome (CS). The normalization of serum hormones led to the regression of the picture. A 64-year-old man presented with spontaneous globe luxation of the left eye after a 6-month history of bilateral, painless, and slowly progressive exophthalmos. The patient had been receiving weekly infusions of methylprednisone over the previous 6 months. His best-corrected visual acuity (BCVA) at presentation was 20/40 in the right eye and 20/20 in the left eye. The patient demonstrated full extraocular motility. The intraocular pressure (IOP) was elevated in the right eye (24 mHg) and normal in the left eye (18 mmHg). Exophthalmometry demonstrated bilateral proptosis with measurements of 27 mm in the right eye and 28 mm in the left eye. Computed tomography scan of the brain and orbits revealed increased orbital and cervical fat. Clinical, radiographic and serologic findings ruled out potential diagnoses including orbital metastasis, thyroid orbitopathy, carotid-cavernous fistula, and idiopathic orbital pseudotumor. Clinical suspicion of iatrogenic CS was high, and additional serologic testing confirmed the diagnosis. Exophthalmos is an uncommon sign of CS, but to our knowledge, this is the first reported case of spontaneous globe luxation secondary to CS. In our case, normalization of cortisol was sufficient to resolve the clinical symptoms and eliminated the need for surgical intervention such as orbital decompression surgery.

  15. Spontaneous prediction error generation in schizophrenia.

    Directory of Open Access Journals (Sweden)

    Yuichi Yamashita

    Full Text Available Goal-directed human behavior is enabled by hierarchically-organized neural systems that process executive commands associated with higher brain areas in response to sensory and motor signals from lower brain areas. Psychiatric diseases and psychotic conditions are postulated to involve disturbances in these hierarchical network interactions, but the mechanism for how aberrant disease signals are generated in networks, and a systems-level framework linking disease signals to specific psychiatric symptoms remains undetermined. In this study, we show that neural networks containing schizophrenia-like deficits can spontaneously generate uncompensated error signals with properties that explain psychiatric disease symptoms, including fictive perception, altered sense of self, and unpredictable behavior. To distinguish dysfunction at the behavioral versus network level, we monitored the interactive behavior of a humanoid robot driven by the network. Mild perturbations in network connectivity resulted in the spontaneous appearance of uncompensated prediction errors and altered interactions within the network without external changes in behavior, correlating to the fictive sensations and agency experienced by episodic disease patients. In contrast, more severe deficits resulted in unstable network dynamics resulting in overt changes in behavior similar to those observed in chronic disease patients. These findings demonstrate that prediction error disequilibrium may represent an intrinsic property of schizophrenic brain networks reporting the severity and variability of disease symptoms. Moreover, these results support a systems-level model for psychiatric disease that features the spontaneous generation of maladaptive signals in hierarchical neural networks.

  16. Preconceptional folate supplementation and the risk of spontaneous preterm birth: a cohort study.

    Directory of Open Access Journals (Sweden)

    Radek Bukowski

    2009-05-01

    Full Text Available BACKGROUND: Low plasma folate concentrations in pregnancy are associated with preterm birth. Here we show an association between preconceptional folate supplementation and the risk of spontaneous preterm birth. METHODS AND FINDINGS: In a cohort of 34,480 low-risk singleton pregnancies enrolled in a study of aneuploidy risk, preconceptional folate supplementation was prospectively recorded in the first trimester of pregnancy. Duration of pregnancy was estimated based on first trimester ultrasound examination. Natural length of pregnancy was defined as gestational age at delivery in pregnancies with no medical or obstetrical complications that may have constituted an indication for delivery. Spontaneous preterm birth was defined as duration of pregnancy between 20 and 37 wk without those complications. The association between preconceptional folate supplementation and the risk of spontaneous preterm birth was evaluated using survival analysis. Comparing to no supplementation, preconceptional folate supplementation for 1 y or longer was associated with a 70% decrease in the risk of spontaneous preterm delivery between 20 and 28 wk (41 [0.27%] versus 4 [0.04%] spontaneous preterm births, respectively; HR 0.22, 95% confidence interval [CI] 0.08-0.61, p = 0.004 and a 50% decrease in the risk of spontaneous preterm delivery between 28 and 32 wk (58 [0.38%] versus 12 [0.18%] preterm birth, respectively; HR 0.45, 95% CI 0.24-0.83, p = 0.010. Adjustment for maternal characteristics age, race, body mass index, education, marital status, smoking, parity, and history of prior preterm birth did not have a material effect on the association between folate supplementation for 1 y or longer and spontaneous preterm birth between 20 and 28, and 28 to 32 wk (adjusted HR 0.31, 95% CI 0.11-0.90, p = 0.031 and 0.53, 0.28-0.99, p = 0.046, respectively. Preconceptional folate supplementation was not significantly associated with the risk of spontaneous preterm birth

  17. Preconceptional Folate Supplementation and the Risk of Spontaneous Preterm Birth: A Cohort Study

    Science.gov (United States)

    Bukowski, Radek; Malone, Fergal D.; Porter, Flint T.; Nyberg, David A.; Comstock, Christine H.; Hankins, Gary D. V.; Eddleman, Keith; Gross, Susan J.; Dugoff, Lorraine; Craigo, Sabrina D.; Timor-Tritsch, Ilan E.; Carr, Stephen R.; Wolfe, Honor M.; D'Alton, Mary E.

    2009-01-01

    Background Low plasma folate concentrations in pregnancy are associated with preterm birth. Here we show an association between preconceptional folate supplementation and the risk of spontaneous preterm birth. Methods and Findings In a cohort of 34,480 low-risk singleton pregnancies enrolled in a study of aneuploidy risk, preconceptional folate supplementation was prospectively recorded in the first trimester of pregnancy. Duration of pregnancy was estimated based on first trimester ultrasound examination. Natural length of pregnancy was defined as gestational age at delivery in pregnancies with no medical or obstetrical complications that may have constituted an indication for delivery. Spontaneous preterm birth was defined as duration of pregnancy between 20 and 37 wk without those complications. The association between preconceptional folate supplementation and the risk of spontaneous preterm birth was evaluated using survival analysis. Comparing to no supplementation, preconceptional folate supplementation for 1 y or longer was associated with a 70% decrease in the risk of spontaneous preterm delivery between 20 and 28 wk (41 [0.27%] versus 4 [0.04%] spontaneous preterm births, respectively; HR 0.22, 95% confidence interval [CI] 0.08–0.61, p = 0.004) and a 50% decrease in the risk of spontaneous preterm delivery between 28 and 32 wk (58 [0.38%] versus 12 [0.18%] preterm birth, respectively; HR 0.45, 95% CI 0.24–0.83, p = 0.010). Adjustment for maternal characteristics age, race, body mass index, education, marital status, smoking, parity, and history of prior preterm birth did not have a material effect on the association between folate supplementation for 1 y or longer and spontaneous preterm birth between 20 and 28, and 28 to 32 wk (adjusted HR 0.31, 95% CI 0.11–0.90, p = 0.031 and 0.53, 0.28–0.99, p = 0.046, respectively). Preconceptional folate supplementation was not significantly associated with the risk of spontaneous preterm

  18. Comparison of evoked vs. spontaneous tics in a patient with trigeminal neuralgia (tic doloureux

    Directory of Open Access Journals (Sweden)

    Aiello-Lammens Matthew

    2007-11-01

    Full Text Available Abstract A 53-year old woman with tic doloureaux, affecting her right maxillary division of the trigeminal nerve (V2, could elicit shooting pains by slightly tapping her teeth when off medication. The pains, which she normally rated as > 6/10 on a visual analog scale (VAS, were electric shock-like in nature. She had no other spontaneous or ongoing background pain affecting the region. Based on her ability to elicit these tics, functional magnetic resonance imaging (fMRI was performed while she produced brief shocks every 2 minutes on cue (evoked pain over a 20 min period. In addition, she had 1–2 spontaneous shocks manifested between these evoked pains over the course of functional image acquisition. Increased fMRI activation for both evoked and spontaneous tics was observed throughout cortical and subcortical structures commonly observed in experimental pain studies with healthy subjects; including the primary somatosensory cortex, insula, anterior cingulate, and thalamus. Spontaneous tics produced more decrease in signals in a number of regions including the posterior cingulate cortex and amygdala, suggesting that regions known to be involved in expectation/anticipation may have been activated for the evoked, but not spontaneous, tics. In this patient there were large increases in activation observed in the frontal regions, including the anterior cingulate cortex and the basal ganglia. Spontaneous tics showed increased activation in classic aversion circuitry that may contribute to increased levels of anxiety. We believe that this is the first report of functional imaging of brain changes in tic-doloureaux.

  19. Comparison of evoked vs. spontaneous tics in a patient with trigeminal neuralgia (tic doloureux).

    Science.gov (United States)

    Borsook, David; Moulton, Eric A; Pendse, Gautam; Morris, Susie; Cole, Sadie H; Aiello-Lammens, Matthew; Scrivani, Steven; Becerra, Lino R

    2007-11-06

    A 53-year old woman with tic doloureaux, affecting her right maxillary division of the trigeminal nerve (V2), could elicit shooting pains by slightly tapping her teeth when off medication. The pains, which she normally rated as > 6/10 on a visual analog scale (VAS), were electric shock-like in nature. She had no other spontaneous or ongoing background pain affecting the region. Based on her ability to elicit these tics, functional magnetic resonance imaging (fMRI) was performed while she produced brief shocks every 2 minutes on cue (evoked pain) over a 20 min period. In addition, she had 1-2 spontaneous shocks manifested between these evoked pains over the course of functional image acquisition. Increased fMRI activation for both evoked and spontaneous tics was observed throughout cortical and subcortical structures commonly observed in experimental pain studies with healthy subjects; including the primary somatosensory cortex, insula, anterior cingulate, and thalamus. Spontaneous tics produced more decrease in signals in a number of regions including the posterior cingulate cortex and amygdala, suggesting that regions known to be involved in expectation/anticipation may have been activated for the evoked, but not spontaneous, tics. In this patient there were large increases in activation observed in the frontal regions, including the anterior cingulate cortex and the basal ganglia. Spontaneous tics showed increased activation in classic aversion circuitry that may contribute to increased levels of anxiety. We believe that this is the first report of functional imaging of brain changes in tic-doloureaux.

  20. A New Mouse Model That Spontaneously Develops Chronic Liver Inflammation and Fibrosis

    Science.gov (United States)

    Fransén-Pettersson, Nina; Duarte, Nadia; Nilsson, Julia; Lundholm, Marie; Mayans, Sofia; Larefalk, Åsa; Hannibal, Tine D.; Hansen, Lisbeth; Schmidt-Christensen, Anja; Ivars, Fredrik; Cardell, Susanna; Palmqvist, Richard; Rozell, Björn

    2016-01-01

    Here we characterize a new animal model that spontaneously develops chronic inflammation and fibrosis in multiple organs, the non-obese diabetic inflammation and fibrosis (N-IF) mouse. In the liver, the N-IF mouse displays inflammation and fibrosis particularly evident around portal tracts and central veins and accompanied with evidence of abnormal intrahepatic bile ducts. The extensive cellular infiltration consists mainly of macrophages, granulocytes, particularly eosinophils, and mast cells. This inflammatory syndrome is mediated by a transgenic population of natural killer T cells (NKT) induced in an immunodeficient NOD genetic background. The disease is transferrable to immunodeficient recipients, while polyclonal T cells from unaffected syngeneic donors can inhibit the disease phenotype. Because of the fibrotic component, early on-set, spontaneous nature and reproducibility, this novel mouse model provides a unique tool to gain further insight into the underlying mechanisms mediating transformation of chronic inflammation into fibrosis and to evaluate intervention protocols for treating conditions of fibrotic disorders. PMID:27441847

  1. Connections with nature and environmental behaviors.

    Science.gov (United States)

    Geng, Liuna; Xu, Jingke; Ye, Lijuan; Zhou, Wenjun; Zhou, Kexin

    2015-01-01

    The influence of environmental attitudes on environmental behaviors has long been discussed. However, few studies have addressed the foundation of such attitudes. In the present study, we explored primitive belief underlying environmental attitudes, i.e., connections with nature, and its relationship with pro-environmental behaviors. Specifically, we used scales, a computerized Implicit Association Test, and a situational simulation experiment to examine both explicit and implicit connections with nature, both deliberate and spontaneous environmental behaviors, and to find correlations between environmental connectedness and environmental behaviors. Results showed that explicit connectedness was positively correlated with deliberate environmental behaviors, while implicit connectedness was positively correlated with spontaneous environmental behaviors. Additionally, explicit and implicit connectedness was independent of each other. In conclusion, the current study confirms the positive role played by connections with nature in promoting environmental behavior, and accordingly suggests means to encourage pro-environmental behavior by enhancing people's connectedness to nature.

  2. Polar cap flow channel events: spontaneous and driven responses

    Directory of Open Access Journals (Sweden)

    P. E. Sandholt

    2010-11-01

    Full Text Available We present two case studies of specific flow channel events appearing at the dusk and/or dawn polar cap boundary during passage at Earth of interplanetary (IP coronal mass ejections (ICMEs on 10 January and 25 July 2004. The channels of enhanced (>1 km/s antisunward convection are documented by SuperDARN radars and dawn-dusk crossings of the polar cap by the DMSP F13 satellite. The relationship with Birkeland currents (C1–C2 located poleward of the traditional R1–R2 currents is demonstrated. The convection events are manifest in ground magnetic deflections obtained from the IMAGE (International Monitor for Auroral Geomagnetic Effects Svalbard chain of ground magnetometer stations located within 71–76° MLAT. By combining the ionospheric convection data and the ground magnetograms we are able to study the temporal behaviour of the convection events. In the two ICME case studies the convection events belong to two different categories, i.e., directly driven and spontaneous events. In the 10 January case two sharp southward turnings of the ICME magnetic field excited corresponding convection events as detected by IMAGE and SuperDARN. We use this case to determine the ground magnetic signature of enhanced flow channel events (the NH-dusk/By<0 variant. In the 25 July case a several-hour-long interval of steady southwest ICME field (Bz<0; By<0 gave rise to a long series of spontaneous convection events as detected by IMAGE when the ground stations swept through the 12:00–18:00 MLT sector. From the ground-satellite conjunction on 25 July we infer the pulsed nature of the polar cap ionospheric flow channel events in this case. The typical duration of these convection enhancements in the polar cap is 10 min.

  3. A neurodynamic account of spontaneous behaviour.

    Science.gov (United States)

    Namikawa, Jun; Nishimoto, Ryunosuke; Tani, Jun

    2011-10-01

    The current article suggests that deterministic chaos self-organized in cortical dynamics could be responsible for the generation of spontaneous action sequences. Recently, various psychological observations have suggested that humans and primates can learn to extract statistical structures hidden in perceptual sequences experienced during active environmental interactions. Although it has been suggested that such statistical structures involve chunking or compositional primitives, their neuronal implementations in brains have not yet been clarified. Therefore, to reconstruct the phenomena, synthetic neuro-robotics experiments were conducted by using a neural network model, which is characterized by a generative model with intentional states and its multiple timescales dynamics. The experimental results showed that the robot successfully learned to imitate tutored behavioral sequence patterns by extracting the underlying transition probability among primitive actions. An analysis revealed that a set of primitive action patterns was embedded in the fast dynamics part, and the chaotic dynamics of spontaneously sequencing these action primitive patterns was structured in the slow dynamics part, provided that the timescale was adequately set for each part. It was also shown that self-organization of this type of functional hierarchy ensured robust action generation by the robot in its interactions with a noisy environment. This article discusses the correspondence of the synthetic experiments with the known hierarchy of the prefrontal cortex, the supplementary motor area, and the primary motor cortex for action generation. We speculate that deterministic dynamical structures organized in the prefrontal cortex could be essential because they can account for the generation of both intentional behaviors of fixed action sequences and spontaneous behaviors of pseudo-stochastic action sequences by the same mechanism.

  4. SPONTANEOUS POTENTIAL INVESTIGATIONS IN SEMENIC MOUNTAINS

    Directory of Open Access Journals (Sweden)

    P. URDEA

    2014-11-01

    Full Text Available Spontaneous Potential Investigations in Semenic Mountains. The use of geophysical methods such as that of Spontaneous Potential (SP to investigate areas where the geomorphological processes occur, has the role to identify less visible processes as for example subcutaneous erosion or piping, subsoil water drainage and finding specific spatial differences of these processes. Comparative study of these sites allows correlation between geomorphological factors, soil and climate, but also to observe the evolution of subsurface erosion or underground water infiltration over time. During this investigation a series of mesh grids have been made in areas with different characteristics (lithology, pedology, slope, exposition, etc. at different time periods in order to spot and analyse the change in data in the chosen sites, various conditions given. Values expressed in millivolts (mV obtained by the Spontaneous Potential method have been put into an algorithm for interpolation looking to yield a pattern of values of what is happening in the soil during that period of time. Thus, in the autumn, the investigation site at the nivation niche Baia Vulturilor, returned values of between -22.6 mV and 65.6 mV, while in spring in the same site, values were within the range of -14.4 mV / 30.1 mV. On the other hand, on the site of the cryopediment under the Semenic peak, in the spring, return values ranged from -40.4 mV and -1.1 mV. A particular case is that of the glacis near Piatra Goznei peak; in this area anthropogenic electricity influences on soil can be found. Based on some models a trend of water movement in the soil could be established, this depending heavily on the amount of precipitation infiltration, local lithology, depth of soil and their structure, and evapotranspiration process. Water movement in the soil may be a correlation with sediment movement in soil horizons and instability manifested on the slopes.

  5. A neurodynamic account of spontaneous behaviour.

    Directory of Open Access Journals (Sweden)

    Jun Namikawa

    2011-10-01

    Full Text Available The current article suggests that deterministic chaos self-organized in cortical dynamics could be responsible for the generation of spontaneous action sequences. Recently, various psychological observations have suggested that humans and primates can learn to extract statistical structures hidden in perceptual sequences experienced during active environmental interactions. Although it has been suggested that such statistical structures involve chunking or compositional primitives, their neuronal implementations in brains have not yet been clarified. Therefore, to reconstruct the phenomena, synthetic neuro-robotics experiments were conducted by using a neural network model, which is characterized by a generative model with intentional states and its multiple timescales dynamics. The experimental results showed that the robot successfully learned to imitate tutored behavioral sequence patterns by extracting the underlying transition probability among primitive actions. An analysis revealed that a set of primitive action patterns was embedded in the fast dynamics part, and the chaotic dynamics of spontaneously sequencing these action primitive patterns was structured in the slow dynamics part, provided that the timescale was adequately set for each part. It was also shown that self-organization of this type of functional hierarchy ensured robust action generation by the robot in its interactions with a noisy environment. This article discusses the correspondence of the synthetic experiments with the known hierarchy of the prefrontal cortex, the supplementary motor area, and the primary motor cortex for action generation. We speculate that deterministic dynamical structures organized in the prefrontal cortex could be essential because they can account for the generation of both intentional behaviors of fixed action sequences and spontaneous behaviors of pseudo-stochastic action sequences by the same mechanism.

  6. Chronic Hepatitis B with Spontaneous Severe Acute Exacerbation

    Directory of Open Access Journals (Sweden)

    Wei-Lun Tsai

    2015-11-01

    Full Text Available Chronic hepatitis B virus (HBV infection is a major global health problem with an estimated 400 million HBV carriers worldwide. In the natural history of chronic hepatitis B (CHB, spontaneous acute exacerbation (AE is not uncommon, with a cumulative incidence of 10%–30% every year. While exacerbations can be mild, some patients may develop hepatic decompensation and even die. The underlying pathogenesis is possibly related to the activation of cytotoxic T lymphocyte-mediated immune response against HBV. An upsurge of serum HBV DNA usually precedes the rise of alanine aminotransferase (ALT and bilirubin. Whether antiviral treatment can benefit CHB with severe AE remains controversial, but early nucleos(tide analogues treatment seemed to be associated with an improved outcome. There has been no randomized study that compared the effects of different nucleos(tide analogues (NA in the setting of CHB with severe AE. However, potent NAs with good resistance profiles are recommended. In this review, we summarized current knowledge regarding the natural history, pathogenetic mechanisms, and therapeutic options of CHB with severe AE.

  7. Spontaneous Chiral Symmetry Breaking as Condensation of Dynamical Chirality

    CERN Document Server

    Alexandru, Andrei

    2012-01-01

    The occurrence of spontaneous chiral symmetry breaking (SChSB) is equivalent to sufficient abundance of Dirac near-zeromodes. However, dynamical mechanism leading to breakdown of chiral symmetry should be naturally reflected in chiral properties of the modes. Here we offer such connection, presenting evidence that SChSB in QCD proceeds via the appearance of modes exhibiting dynamical tendency for local chiral polarization. These modes form a band of finite width Lambda_ch (chiral polarization scale) around the surface of otherwise anti--polarized Dirac sea, and condense. Lambda_ch characterizes the dynamics of the breaking phenomenon and can be converted to a quark mass scale, thus offering conceptual means to determine which quarks of nature are governed by broken chiral dynamics. It is proposed that, within the context of SU(3) gauge theories with fundamental Dirac quarks, mode condensation is equivalent to chiral polarization, making Lambda_ch an "order parameter" of SChSB. Several uses of these features, ...

  8. A Semi-analytic Criterion for the Spontaneous Initiation of Carbon Detonations in White Dwarfs

    Science.gov (United States)

    Garg, Uma; Chang, Philip

    2017-02-01

    Despite over 40 years of active research, the nature of the white dwarf progenitors of SNe Ia remains unclear. However, in the last decade, various progenitor scenarios have highlighted the need for detonations to be the primary mechanism by which these white dwarfs are consumed, but it is unclear how these detonations are triggered. In this paper we study how detonations are spontaneously initiated due to temperature inhomogeneities, e.g., hotspots, in burning nuclear fuel in a simplified physical scenario. Following the earlier work by Zel’Dovich, we describe the physics of detonation initiation in terms of the comparison between the spontaneous wave speed and the Chapman–Jouguet speed. We develop an analytic expression for the spontaneous wave speed and utilize it to determine a semi-analytic criterion for the minimum size of a hotspot with a linear temperature gradient between a peak and base temperature for which detonations in burning carbon–oxygen material can occur. Our results suggest that spontaneous detonations may easily form under a diverse range of conditions, likely allowing a number of progenitor scenarios to initiate detonations that burn up the star.

  9. Spontaneously Emerging Patterns in Human Visual Cortex Reflect Responses to Naturalistic Sensory Stimuli.

    Science.gov (United States)

    Wilf, Meytal; Strappini, Francesca; Golan, Tal; Hahamy, Avital; Harel, Michal; Malach, Rafael

    2017-01-01

    In the absence of stimulus or task, the cortex spontaneously generates rich and consistent functional connectivity patterns (termed resting state networks) which are evident even within individual cortical areas. We and others have previously hypothesized that habitual cortical network activations during daily life contribute to the shaping of these connectivity patterns. Here we tested this hypothesis by comparing, using blood oxygen level-dependent-functional magnetic resonance imaging, the connectivity patterns that spontaneously emerge during rest in retinotopic visual areas to the patterns generated by naturalistic visual stimuli (repeated movie segments). These were then compared with connectivity patterns produced by more standard retinotopic mapping stimuli (polar and eccentricity mapping). Our results reveal that the movie-driven patterns were significantly more similar to the spontaneously emerging patterns, compared with the connectivity patterns of either eccentricity or polar mapping stimuli. Intentional visual imagery of naturalistic stimuli was unlikely to underlie these results, since they were duplicated when participants were engaged in an auditory task. Our results suggest that the connectivity patterns that appear during rest better reflect naturalistic activations rather than controlled, artificially designed stimuli. The results are compatible with the hypothesis that the spontaneous connectivity patterns in human retinotopic areas reflect the statistics of cortical coactivations during natural vision. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  10. Spontaneous expression of magnetic compass orientation in an epigeic rodent: the bank vole, Clethrionomys glareolus

    Science.gov (United States)

    Oliveriusová, Ludmila; Němec, Pavel; Pavelková, Zuzana; Sedláček, František

    2014-07-01

    Magnetoreception has been convincingly demonstrated in only a few mammalian species. Among rodents, magnetic compass orientation has been documented in four species of subterranean mole rats and two epigeic (i.e. active above ground) species—the Siberian hamster and the C57BL/6J mouse. The mole rats use the magnetic field azimuth to determine compass heading; their directional preference is spontaneous and unimodal, and their magnetic compass is magnetite-mediated. By contrast, the primary component of orientation response is learned in the hamster and the mouse, but both species also exhibit a weak spontaneous bimodal preference in the natural magnetic field. To determine whether the magnetic compass of wild epigeic rodents features the same functional properties as that of laboratory rodents, we investigated magnetic compass orientation in the bank vole Clethrionomys glareolus (Cricetidae, Rodentia). The voles exhibited a robust spontaneous bimodal directional preference, i.e. built nests and slept preferentially along the north-south axis, and deflected their directional preference according to a shift in the direction of magnetic north, clearly indicating that they were deriving directional information from the magnetic field. Thus, bimodal, axially symmetrical directional choice seems to be a common feature shared by epigeic rodents. However, spontaneous directional preference in the bank vole appeared to be more pronounced than that reported in the hamster and the mouse. These findings suggest that bank voles are well suited for future studies investigating the adaptive significance and mechanisms of magnetic orientation in epigeic rodents.

  11. QCD emergent from spontaneous breakdown of relativity

    CERN Document Server

    Nishimura, Kimihide

    2016-01-01

    Spontaneous violation of relativistic invariance of the vacuum can derive quantum chromodynamics from an U(1) Higgs model including fermions, if the emergent theory is Lorentz invariant. In this model, the vacuum becomes anisotropic, and a fermion created on a triplet of spin-one vacua acquires degeneracy analogous to the color degrees of freedom. The Nambu-Goldstone bosons originating from the breakdown of rotational symmetry provide the quasi fermions with SU(3)$\\times$U(1) effective interactions, which are interpretable as mediated by gluons and photons. The confinement of quasi quarks as well as that of Nambu-Goldstone gluons follow from the Lorentz invariance of the emergent theory.

  12. Spontaneous fluxoid formation in superconducting loops

    DEFF Research Database (Denmark)

    Monaco, R.; Mygind, Jesper; Rivers, R.

    2009-01-01

    a scaling relation on the quenching time τQ, as one would expect if the transition took place as fast as causality permits. However, the observed Zurek-Kibble scaling exponent σ=0.62±0.15 is two times larger than anticipated for large loops. Assuming Gaussian winding number densities we show......We report on the experimental verification of the Zurek-Kibble scenario in an isolated superconducting ring over a wide parameter range. The probability of creating a single flux quantum spontaneously during the fast normal-superconducting phase transition of a wide Nb loop clearly follows...

  13. Angyomatous vocal polypus: a complete spontaneous regression

    Directory of Open Access Journals (Sweden)

    Edmir Américo Lourenço

    Full Text Available The authors describe a male patient who had malignant lymphoma seven years ago which remitted with chemotherapy.Two years ago he developed dysphonia. An unilateral, pediculate smooth red lesion on the right vocal fold was later discovered. Even without benefit of medicamentosus treatment, the patient refused surgery. In a reevaluation using rigid telescopy of the larynx two years later, the lesion had disappeared, completely and spontaneously. As there are no existing publications on this topic, this case report is an alert that surgery should be recommended with extreme caution in this type of vocal disease.

  14. [Spontaneous pneumothorax: unusual manifestation of pulmonary hamartochondroma].

    Science.gov (United States)

    Serhane, Hind; Afandi, Oussama Abdessalam; Msougar, Yassine; Amro, Lamyae

    2016-01-01

    Hamartochondroma is a benign tumor of the tracheobronchial tree, often found incidentally and rarely symptomatic. It is more common in men than in women. Its radiological aspect is often evocative. Surgery is indicated for large and/or symptomatic tumors. Histological diagnosis usually poses no difficulty We report the case of a 30-year-old young patient with no particular past medical history and with spontaneous pneumothorax revealing a large sized hamartochondroma. This rare association could be explained by the fact that tumors of fairly anarchic composition may contain cyst formations that may rupture into the pleura causing effusions.

  15. Spontaneously broken Lorentz symmetry and gravity

    CERN Document Server

    Jacobson, T; Jacobson, Ted; Mattingly, David

    2000-01-01

    We study a generally covariant model in which local Lorentz invariance is broken "spontaneously" by a dynamical unit timelike vector field $u^a$---the "aether". Such a model makes it possible to study the gravitational and cosmological consequences of preferred frame effects, such as ``variable speed of light" or high frequency dispersion, while preserving a generally covariant metric theory of gravity. In this paper we restrict attention to an action for an effective theory of the aether which involves only the antisymmetrized derivative $\

  16. Spontaneous hygroma in intracranial arachnoid cyst

    Energy Technology Data Exchange (ETDEWEB)

    Agnoli, A.L.

    1984-06-01

    Anamnesis and treatment of two cases of arachnoid cysts extending into the subarachnoid space are described. No traumatic incident was discovered in the previous history of these two patients. The causal genesis of neurological signs of deficiency in patients with arachnoid and acquired cysts is discussed. However, the cause of the development of a subdural hygroma in arachnoid cysts remains unclarified. CT findings of arachnoid cysts with a hypodense zone between brain surface and the vault of the cranium always require an investigation into the possibility of a spontaneous emptying of the cyst or of a congenital and not only localised extension of the cyst itself.

  17. Fracture of maternal sternum during spontaneous delivery.

    Science.gov (United States)

    Stubert, J; Gerber, B

    2009-12-01

    We report of a maternal sternal fracture during a spontaneous delivery in a 31-year-old primipara without a suitable trauma. The putative mechanism of fracture was strong hyperflexion of the thoracic spine and additional cervical flexion with pushing the chin to the thorax due to active management of labour. The history of the healthy woman was free of related risk factors. A possible promoting factor might be pregnancy-induced bone loss. Although there were clear symptoms, the diagnosis of the fracture was delayed by a week because nobody took account of such a possibility.

  18. Spontaneous Epiglottic Hematoma Secondary to Supratherapeutic Anticoagulation

    Directory of Open Access Journals (Sweden)

    Cody A. Koch

    2010-01-01

    Full Text Available Hemorrhage into the soft tissues of the airway represents a potentially life-threatening complication of long-term anticoagulation. We report the case of a chronically anticoagulated 37-year-old male who developed a spontaneous hematoma of the epiglottis secondary to a supra-therapeutic INR. Epiglottic hematoma should be considered in the differential of any anticoagulated patient presenting with upper airway compromise. The airway should be secured in a controlled fashion, and the coagulopathy should be rapidly corrected.

  19. Classification of spontaneous EEG signals in migraine

    Science.gov (United States)

    Bellotti, R.; De Carlo, F.; de Tommaso, M.; Lucente, M.

    2007-08-01

    We set up a classification system able to detect patients affected by migraine without aura, through the analysis of their spontaneous EEG patterns. First, the signals are characterized by means of wavelet-based features, than a supervised neural network is used to classify the multichannel data. For the feature extraction, scale-dependent and scale-independent methods are considered with a variety of wavelet functions. Both the approaches provide very high and almost comparable classification performances. A complete separation of the two groups is obtained when the data are plotted in the plane spanned by two suitable neural outputs.

  20. Neutrino masses and spontaneously broken flavor symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Staudt, Christian

    2014-06-16

    We study the phenomenology of supersymmetric flavor models. We show how the predictions of models based on spontaneously broken non-Abelian discrete flavor symmetries are altered when we include so-called Kaehler corrections. Furthermore, we discuss anomaly-free discrete R symmetries which are compatible with SU(5) unification. We find a set of symmetries compatible with suppressed Dirac neutrino masses and a unique symmetry consistent with the Weinberg operator. We also study a pseudo-anomalous U(1){sub R} symmetry which explains the fermion mass hierarchies and, when amended with additional singlet fields, ameliorates the fine-tuning problem.

  1. Spontaneously generated X-shaped light bullets

    CERN Document Server

    Trapani, P D; Piskarskas, A; Jedrkiewicz, O; Trull, J; Conti, C; Trillo, S

    2003-01-01

    We observe the formation of an intense optical wavepacket fully localized in all dimensions, i.e. both longitudinally (in time) and in the transverse plane, with an extension of a few tens of fsec and microns, respectively. Our measurements show that the self-trapped wave is a X-shaped light bullet spontaneously generated from a standard laser wavepacket via the nonlinear material response (i.e., second-harmonic generation), which extend the soliton concept to a new realm, where the main hump coexists with conical tails which reflect the symmetry of linear dispersion relationship.

  2. Spontaneous symmetry breaking in a classical particle

    CERN Document Server

    Sánchez, L A; Sanchez, Luis Alberto; Mahecha, Jorge

    2003-01-01

    Due to the fact that only matter fields have phase, frequently is believed that the gauge principle can induce gauge fields only in quantum systems. But this is not necessary. This paper, of pedagogical scope, presents a classical system constituted by a particle in a classical potential, which is used as a model to illustrate the gauge principle and the spontaneous symmetry breaking. Those concepts appear in the study of second order phase transitions. Ferroelectricity, ferromagnetism, superconductivity, plasmons in a free electron gas, and the mass of vector bosons in the gauge field Yang-Mills theories, are some of the phenomena in which these transitions occur.

  3. Spontaneous Resolution of Vitreomacular Traction in Two Patients with Diabetic Macular Edema

    Directory of Open Access Journals (Sweden)

    David R.P. Almeida

    2014-02-01

    Full Text Available The nature of the vitreoretinal interface in conditions like diabetic macular edema (DME remains incompletely understood. Furthermore, it is not clear what the role of pharmacological enzymatic vitreolysis will play in cases of vitreomacular traction (VMT associated with macular disease like DME. We describe the spontaneous resolution of VMT in 2 patients with DME. As both surgical and pharmacologic interventions have been suggested to treat DME in the setting of VMT, we feel that a clarification of the nomenclature and reporting of these cases of natural history may be useful in more fully understanding the complex decision-making involved when determining whether to treat this subset of patients.

  4. Amplified spontaneous emission of Rhodamine 6G embedded in pure deoxyribonucleic acid

    Science.gov (United States)

    Rau, Ileana; Szukalski, Adam; Sznitko, Lech; Miniewicz, Andrzej; Bartkiewicz, Stanislaw; Kajzar, Francois; Sahraoui, Bouchta; Mysliwiec, Jaroslaw

    2012-10-01

    Deoxyribonucleic acid (DNA) is commonly viewed as a genetic information carrier. However, now it is recognized as a nanomaterial, rather than as a biological material, in the research field of nanotechnology. Here, we show that using pure DNA, doped with rhodamine 6G, we are able to observe amplified spontaneous emission (ASE) phenomenon. Moderate ASE threshold, photodegradation, and reasonable gain coefficient observed in this natural host gives some perspectives for practical applications of this system in biophotonics. Obtained results open the way and will be leading to construction of truly bio-lasers using nature made luminophores, such as anthocyanins.

  5. Spontaneous septicaemia with multi-organ dysfunction-a new face for Pantoe agglomerans?

    Institute of Scientific and Technical Information of China (English)

    Kushal Naha; Ramamoorthi; Mukhyaprana Prabhu

    2012-01-01

    Pantoe agglomerans (P. agglomerans) is an unusual cause for sepsis in immunocompetent individuals, especially in the absence of characteristic risk factors. We report one such case occurring in a farmer, manifesting with severe illness. The severe nature of illness and the apparently spontaneous origin of septicemia underline the pathogenic potential of this organism. When coupled with the ubiquity of the organism, there is a definite possibility that this disease may become increasingly frequent in the near future, especially in agronomic countries like India. Further studies on the epidemiology and natural history of this disease are required.

  6. Displaying Nature

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Beijing Museum of Natural History is located in Chongwen District, close to the Temple of Heaven and Tianqiao Theater. It was founded in 1951 and formally named Beijing Museum of Natural History in 1962.

  7. Spontaneous Planar Chiral Symmetry Breaking in Cells

    Science.gov (United States)

    Hadidjojo, Jeremy; Lubensky, David

    Recent progress in animal development has highlighted the central role played by planar cell polarity (PCP) in epithelial tissue morphogenesis. Through PCP, cells have the ability to collectively polarize in the plane of the epithelium by localizing morphogenetic proteins along a certain axis. This allows direction-dependent modulation of tissue mechanical properties that can translate into the formation of complex, non-rotationally invariant shapes. Recent experimental observations[1] show that cells, in addition to being planar-polarized, can also spontaneously develop planar chirality, perhaps in the effort of making yet more complex shapes that are reflection non-invariant. In this talk we will present our work in characterizing general mechanisms that can lead to spontaneous chiral symmetry breaking in cells. We decompose interfacial concentration of polarity proteins in a hexagonal cell packing into irreducible representations. We find that in the case of polar concentration distributions, a chiral state can only be reached from a secondary instability after the cells are polarized. However in the case of nematic distributions, we show that a finite-amplitude (subcritical, or ``first-order'') nematic transition can send the system from disorder directly to a chiral state. In addition, we find that perturbing the system by stretching the hexagonal packing enables direct (supercritical, or ``second-order'') chiral transition in the nematic case. Finally, we do a Landau expansion to study competition between stretch-induced chirality and the tendency towards a non-chiral state in packings that have retained the full 6-fold symmetry.

  8. Spontaneous fission of superheavy nucleus $^{286}$Fl

    CERN Document Server

    Poenaru, Dorin N

    2016-01-01

    The decimal logarithm of spontaneous fission half-life of the superheavy nucleus $^{286}$Fl experimentally determined is $\\log_{10} T_f^{exp} (s) = -0.632$. We present a method to calculate the half-life based on the cranking inertia and the deformation energy, functions of two independent surface coordinates, using the best asymmetric two center shell model. In the first stage we study the statics. At a given mass asymmetry up to about $\\eta=0.5$ the potential barrier has a two hump shape, but for larger $\\eta$ it has only one hump. The touching point deformation energy versus mass asymmetry shows the three minima, produced by shell effects, corresponding to three decay modes: spontaneous fission, cluster decay and $\\alpha$~decay. The least action trajectory is determined in the plane $(R,\\eta)$ where $R$ is the separation distance of the fission fragments and $\\eta$ is the mass asymmetry. We may find a sequence of several trajectories one of which gives the least action. The parametrization with two deforma...

  9. Spontaneous spherical symmetry breaking in atomic confinement

    CERN Document Server

    Sveshnikov, K

    2016-01-01

    The effect of spontaneous breaking of initial SO(3) symmetry is shown to be possible for an H-like atom in the ground state, when it is confined in a spherical box under general boundary conditions of "not going out" through the box surface (i.e. third kind or Robin's ones), for a wide range of physically reasonable values of system parameters. The reason is that such boundary conditions could yield a large magnitude of electronic wavefunction in some sector of the box boundary, what in turn promotes atomic displacement from the box center towards this part of the boundary, and so the underlying SO(3) symmetry spontaneously breaks. The emerging Goldstone modes, coinciding with rotations around the box center, restore the symmetry by spreading the atom over a spherical shell localized at some distances from the box center. Atomic confinement inside the cavity proceeds dynamically -- due to the boundary condition the deformation of electronic wavefunction near the boundary works as a spring, that returns the at...

  10. Cyclin B1 Vaccine Delays Spontaneous Tumors

    Science.gov (United States)

    Laura A, Vella; Min, Yu; Amy, Phillips; Olivera J, Finn

    2012-01-01

    We previously identified cyclin B1-specific T cells and antibodies in cancer patients with cyclin B1+ tumors and also in some healthy individuals. We also demonstrated that these responses may be important in cancer immunosurveillance by showing that vaccination against cyclin B1 prevents growth of transplantable cyclin B1+ tumors in mice. Constitutive overexpression of cyclin B1 was determined to correlate with the lack of p53 function. This allowed us to use p53−/− mice as a model that better approximates human disease. p53−/− mice spontaneously develop cyclin B1+ tumors. At 5–6 weeks of age, when the mice were still healthy with no evidence of tumor, they received the cyclin B1 vaccine and were then observed for tumor growth. We demonstrate that cyclin B1 vaccination can delay spontaneous cyclin B1+ tumor growth and increases median survival of tumor bearing p53−/− mice. PMID:19769738

  11. Spontaneous appearance of snakes in JET

    Energy Technology Data Exchange (ETDEWEB)

    Gill, R.D.; Edwards, A.W.; Pasini, D.; Wolfe, S.W. (Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking)

    1991-01-01

    Tokamaks exhibit a wide variety of mhd activity on the q=1 surface such as sawteeth and the recently discovered snake which is a surprisingly long lived compact region of high density plasma formed on the q=1 surface following pellet injection. More recently, snakes have been observed to form spontaneously in JET at the onset of the sawtooth and also during neutral beam injection. A typical sawtooth onset case shows that when q becomes 1 in or near the plasma centre mhd oscillations are seen with m=n=1 and a variety of frequencies and amplitudes. Immediately after the first sawtooth these are replaced by a snake, which gradually decays in amplitude, but survives several sawtooth crashes. It is probable that these spontaneous snakes have been previously observed in many other machines but classified as m=1 instabilities. For example, during the 'O' mode of sawtooth onset of DIII, or the mhd activity observed early in PBX discharges. Further, JET discharges from as long ago as 1984 had similar mhd activity at early times which, in retrospect, can also probably be identified as due to snakes. It appears that snakes are a much more general phenomena than originally realized. (author) 5 refs., 5 figs.

  12. Rhythmic spontaneous activity in the piriform cortex.

    Science.gov (United States)

    Sanchez-Vives, Maria V; Descalzo, V F; Reig, R; Figueroa, N A; Compte, A; Gallego, R

    2008-05-01

    Slow spontaneous rhythmic activity is generated and propagates in neocortical slices when bathed in an artificial cerebrospinal fluid with ionic concentrations similar to the ones in vivo. This activity is extraordinarily similar to the activation of the cortex in physiological conditions (e.g., slow-wave sleep), thus representing a unique in vitro model to understand how cortical networks maintain and control ongoing activity. Here we have characterized the activity generated in the olfactory or piriform cortex and endopiriform nucleus (piriform network). Because these structures are prone to generate epileptic discharges, it seems critical to understand how they generate and regulate their physiological rhythmic activity. The piriform network gave rise to rhythmic spontaneous activity consisting of a succession of up and down states at an average frequency of 1.8 Hz, qualitatively similar to the corresponding neocortical activity. This activity originated in the deep layers of the piriform network, which displayed higher excitability and denser connectivity. A remarkable difference with neocortical activity was the speed of horizontal propagation (114 mm/s), one order of magnitude faster in the piriform network. Properties of the piriform cortex subserving fast horizontal propagation may underlie the higher vulnerability of this area to epileptic seizures.

  13. Body Mass Index and spontaneous miscarriage.

    LENUS (Irish Health Repository)

    Turner, Michael J

    2012-02-01

    OBJECTIVE: We compared the incidence of spontaneous miscarriage in women categorised as obese, based on a Body Mass Index (BMI) >29.9 kg\\/m(2), with women in other BMI categories. STUDY DESIGN: In a prospective observational study conducted in a university teaching hospital, women were enrolled at their convenience in the first trimester after a sonogram confirmed an ongoing singleton pregnancy with fetal heart activity present. Maternal height and weight were measured digitally and BMI calculated. Maternal body composition was measured by advanced bioelectrical impedance analysis. RESULTS: In 1200 women, the overall miscarriage rate was 2.8% (n=33). The mean gestational age at enrolment was 9.9 weeks. In the obese category (n=217), the miscarriage rate was 2.3% compared with 3.3% in the overweight category (n=329), and 2.3% in the normal BMI group (n=621). There was no difference in the mean body composition parameters, particularly fat mass parameters, between those women who miscarried and those who did not. CONCLUSIONS: In women with sonographic evidence of fetal heart activity in the first trimester, the rate of spontaneous miscarriage is low and is not increased in women with BMI>29.9 kg\\/m(2) compared to women in the normal BMI category.

  14. Five cases of asymptomatic spontaneous pneumothorax.

    Science.gov (United States)

    Kadokura, M; Nonaka, M; Yamamoto, S; Kataoka, D; Tanio, N; Iyano, K; Oki, A; Kawada, T; Takaba, T

    1999-06-01

    Asymptomatic spontaneous pneumothorax (ASPT) is an uncommon condition. Between January 1, 1989 and December 31, 1997, 269 patients were admitted to our department with spontaneous pneumothorax. Of the 269 patients, 5 had no symptoms at the time of discovery. Their ages ranged from 15 to 61 years (mean, 37.8 years), and all of them were male. Of the 5 patients with no complaints, 2 had bilateral metachronous pneumothoraces and 3 had hemilateral pneumothorax. All of these ASPTs were revealed by chest roentgenographs taken during medical examinations or follow-up studies relating to other diseases. The mean value of body mass index (BMI) was 19.96 +/- 1.4 (range 18.7 - 22.1). Two of the 5 patients underwent bilateral partial lung resection. Histopathological examination of the resected specimens showed elastofibrosis, scar formation, and an interruption of the elastic fiber of the pleura. In these 5 cases, clinical courses were uneventful, and relapse of the pneumothorax did not occur. Clinical physicians should be aware of the possibility of asymptomatic pneumothorax, as well as the optimal radiographic techniques for revealing small pneumothoraces.

  15. Spontaneous wound dehiscence after penetrating keratoplasty

    Institute of Scientific and Technical Information of China (English)

    Alireza; Foroutan; Seyed; Ali; Tabatabaei; Mahmoud; Jabbarvand; Behrouz; Reza; Zarei; Mohammad; Soleimani

    2014-01-01

    Spontaneous wound separation may be developed even months after suture removal especially in the context of long-term corticosteroid therapy. A 68-yearold Caucasian woman presented to our cornea clinic with spontaneous wound dehiscence after her third penetrating keratoplasty(PKP) which was performed three years ago. An Ahmed glaucoma valve(New World Medical, Ranchos Cucamonga, CA) was inserted ten months after the third PKP, which successfully controlled intraocular pressure(IOP). At the examination, the last sutures were removed eight months ago and she was using flourometholone 0.1%(Sina Darou, Tehran, Iran)with a dose of once a day. There was one quadrant of wound dehiscence from 8 to 11 o`clock associated with anterior wound gape and severe corneal edema.Resuturing was performed for the patient. At the one month examination, the corneal edema was resolved and best corrected visual acuity was 20/200 mainly due to previous glaucomatous optic neuropathy. Caution about the prolonged use of corticosteroids is necessary. Topical immunosuppressives could be a promising choice in this field.

  16. Spontaneous ad hoc mobile cloud computing network.

    Science.gov (United States)

    Lacuesta, Raquel; Lloret, Jaime; Sendra, Sandra; Peñalver, Lourdes

    2014-01-01

    Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes.

  17. [Analysis of Spontaneously Reported Adverse Events].

    Science.gov (United States)

    Nakamura, Mitsuhiro

    2016-01-01

    Observational study is necessary for the evaluation of drug effectiveness in clinical practice. In recent years, the use of spontaneous reporting systems (SRS) for adverse drug reactions has increased and they have become an important resource for regulatory science. SRS, being the largest and most well-known databases worldwide, are one of the primary tools used for postmarketing surveillance and pharmacovigilance. To analyze SRS, the US Food and Drug Administration Adverse Event Reporting System (FAERS) and the Japanese Adverse Drug Event Report Database (JADER) are reviewed. Authorized pharmacovigilance algorithms were used for signal detection, including the reporting odds ratio. An SRS is a passive reporting database and is therefore subject to numerous sources of selection bias, including overreporting, underreporting, and a lack of a denominator. Despite the inherent limitations of spontaneous reporting, SRS databases are a rich resource and data mining index that provide powerful means of identifying potential associations between drugs and their adverse effects. Our results, which are based on the evaluation of SRS databases, provide essential knowledge that could improve our understanding of clinical issues.

  18. Sloppiness in spontaneously active neuronal networks.

    Science.gov (United States)

    Panas, Dagmara; Amin, Hayder; Maccione, Alessandro; Muthmann, Oliver; van Rossum, Mark; Berdondini, Luca; Hennig, Matthias H

    2015-06-01

    Various plasticity mechanisms, including experience-dependent, spontaneous, as well as homeostatic ones, continuously remodel neural circuits. Yet, despite fluctuations in the properties of single neurons and synapses, the behavior and function of neuronal assemblies are generally found to be very stable over time. This raises the important question of how plasticity is coordinated across the network. To address this, we investigated the stability of network activity in cultured rat hippocampal neurons recorded with high-density multielectrode arrays over several days. We used parametric models to characterize multineuron activity patterns and analyzed their sensitivity to changes. We found that the models exhibited sloppiness, a property where the model behavior is insensitive to changes in many parameter combinations, but very sensitive to a few. The activity of neurons with sloppy parameters showed faster and larger fluctuations than the activity of a small subset of neurons associated with sensitive parameters. Furthermore, parameter sensitivity was highly correlated with firing rates. Finally, we tested our observations from cell cultures on an in vivo recording from monkey visual cortex and we confirm that spontaneous cortical activity also shows hallmarks of sloppy behavior and firing rate dependence. Our findings suggest that a small subnetwork of highly active and stable neurons supports group stability, and that this endows neuronal networks with the flexibility to continuously remodel without compromising stability and function.

  19. Spontaneous low-frequency oscillations in cerebral vessels

    DEFF Research Database (Denmark)

    Schytz, Henrik W; Hansson, Andreas; Phillip, Dorte

    2010-01-01

    The etiology behind and physiological significance of spontaneous oscillations in the low-frequency spectrum in both systemic and cerebral vessels remain unknown. Experimental studies have proposed that spontaneous oscillations in cerebral blood flow reflect impaired cerebral autoregulation (CA......). Analysis of CA by measurement of spontaneous oscillations in the low-frequency spectrum in cerebral vessels might be a useful tool for assessing risk and investigating different treatment strategies in carotid artery disease (CAD) and stroke. We reviewed studies exploring spontaneous oscillations...... coefficients in the time domain are the most frequently used parameters for analyzing spontaneous oscillations in systemic and cerebral vessels. At present, there is no gold standard for analyzing spontaneous oscillations in the low-frequency spectrum, and simplistic models of CA have failed to predict...

  20. Spontaneous ovarian hyperstimulation syndrome following a thawed embryo transfer cycle.

    Science.gov (United States)

    Kim, Mi Kyoung; Won, Hyung Jae; Shim, Sung Han; Cha, Dong Hyun; Yoon, Tae Ki

    2014-09-01

    This article reports a case of spontaneous ovarian hyperstimulation syndrome (OHSS) following a thawed embryo transfer cycle. OHSS, a potentially life-threatening condition, is an iatrogenic complication of controlled ovarian stimulation; therefore, it is very important to prevent and treat OHSS during treatment with ovulation-inducing agents. Despite our efforts to prevent OHSS, in this case, severe spontaneous OHSS occurred, which resulted in uncontrolled preterm labor and a preterm delivery and also persisted for 6 weeks after delivery. Freezing all embryos cannot entirely prevent the development of OHSS because OHSS can occur spontaneously. Although spontaneous OHSS remains a rare event, females with a history of OHSS may have an elevated risk for spontaneous OHSS. We suggest closely monitoring cases of pregnancy following thawed embryo transfer for early diagnosis of spontaneous OHSS and the use of conservative management.

  1. Maternal smoking predicts the risk of spontaneous abortion

    DEFF Research Database (Denmark)

    Nielsen, Ann; Hannibal, Charlotte Gerd; Lindekilde, Bodil Eriksen

    2006-01-01

    was to assess the risk of spontaneous abortion considering smoking prior to pregnancy. METHODS: We performed a nested case-control study using prospective data from a population-based cohort comprising 11,088 women aged 20-29 years. From this cohort, women who experienced either a spontaneous abortion (n=343......BACKGROUND: Few studies have examined smoking prior to pregnancy and the occurrence of spontaneous abortion, as most studies have addressed the risk of spontaneous abortion in relation to smoking during pregnancy. However, results are not entirely consistent. The aim of the present study......) or who gave birth (n=1,578) during follow-up were selected. Associations between self-reported smoking at enrollment and subsequent spontaneous abortion were analyzed by means of multiple logistic regression. RESULTS: The risk of spontaneous abortion in relation to pre-pregnancy smoking showed a clear...

  2. Maternal underweight and the risk of spontaneous abortion

    DEFF Research Database (Denmark)

    Helgstrand, Stine; Andersen, Anne-Marie Nybo

    2005-01-01

    BACKGROUND: To evaluate the risk of spontaneous abortion in relation to maternal pre-pregnant underweight. METHODS: The study was designed as a cohort study within the framework of the Danish National Birth Cohort (DNBC). The participants were a total of 23 821 women recruited consecutively...... spontaneous abortion. Relative risk of spontaneous abortion was calculated as Hazard Ratios using Cox regression with delayed entry. RESULTS: The outcome measure was spontaneous abortion. The hazard ratio for spontaneous abortion in women with a pre-pregnant body mass index (BMI) below 18.5 was 1.24 (95......% confidence limits 0.95-1.63) compared to women with pre-pregnant BMI 18.5-24.9. Women with a BMI of 25 or more had a smaller increase in risk of spontaneous abortion. Adjustment for maternal age, parity, previous miscarriages, and lifestyle factors did not affect the estimates substantially, neither did...

  3. Spontaneous Coronary Artery Dissection: Case Report Review of the Literature

    Directory of Open Access Journals (Sweden)

    Kemal Karaağaç

    2013-03-01

    Full Text Available Spontaneous coronary artery dissection is a rare cause of acute coronary syndrome with a high risk of mortality. The clinical presentation is similar to the atherosclerotic coronary artery disease. The diagnosis is usually made by coronary angiography. Spontaneous coronary artery dissection is more common in women than men. Fast and accurate diagnosis and treatment of spontaneous coronary artery dissection patients improves survival. Therapeutic options include surgery, percutaneous coronary intervention and medical therapy.

  4. Spontaneous globe luxation associated with chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    M Ashok Kumar

    2012-01-01

    Full Text Available Spontaneous globe luxation is a rarely reported condition which can lead to complications like optic neuropathy. Common causes are thyroid eye disease, shallow orbit and floppy eyelid syndrome. We report a case of spontaneous globe luxation with the onset and severity associated with chronic obstructive pulmonary disease (COPD. To our knowledge, this is the first case of spontaneous globe luxation associated with COPD.

  5. General Anesthesia with Preserved Spontaneous Breathing through an Intubation Tube

    Directory of Open Access Journals (Sweden)

    V. V. Moroz

    2010-01-01

    Full Text Available Objective: to study whether spontaneous patient breathing may be preserved during elective operations under general anesthesia with tracheal intubation. Subjects and methods. One hundred and twelve patients undergoing elective surgeries under general endotracheal anesthesia were randomized into 2 groups: 1 patients who had forced mechanical ventilation in the volume-controlled mode and 2 those who received assisted ventilation as spontaneous breathing with mechanical support. Conclusion. The study shows that spontaneous breathing with mechanical support may be safely used during some surgical interventions in patients with baseline healthy lungs. Key words: Pressure Support, assisted ventilation, spontaneous breathing, general anesthesia, lung function.

  6. Spontaneous closure of an ileostomy: A rare occurrence

    Directory of Open Access Journals (Sweden)

    Ashish Saxena

    2015-01-01

    CONCLUSION: Further research is warranted to understand the mechanism behind spontaneous regression of a stoma. Relationship between this event and intestinal tuberculosis or ATT needs to be analysed.

  7. [Spontaneous hemothorax revealing Wegener's vasculitis in a pregnant woman].

    Science.gov (United States)

    Serhane, Hind; Yassine, Msougar; Amro, Lamyae

    2016-01-01

    Spontaneous hemothorax is a rare condition. Its causes are multiple but sometimes they remain unknown. In some patients, thoracotomy may be the only means to determine hemothorax origin. Vasculitis have not been reported as a common cause of spontaneous hemothorax. Pregnancy does not appear to have causal or aggravating effect on spontaneous hemothorax or on vasculitis. We here report the peculiar case of a young patient presenting during pregnancy with spontaneous hemothorax secondary to Wegener's vasculitis. The latter was diagnosed by pleural biopsy performed during exploratory thoracotomy and confirmed by ANCA assays.

  8. Relation Between Stress During Pregnancy and Spontaneous Preterm Birth

    National Research Council Canada - National Science Library

    Ortiz Martínez, Roberth Alirio; Castillo, Alejandro

    2016-01-01

    ...; however, psychopathological components emerge as potentially important risk factors. To determine the relationship between the presence of stress during pregnancy and spontaneous preterm birth...

  9. Using the Natural Language Paradigm (NLP) to Increase Vocalizations of Older Adults with Cognitive Impairments

    Science.gov (United States)

    LeBlanc, Linda A.; Geiger, Kaneen B.; Sautter, Rachael A.; Sidener, Tina M.

    2007-01-01

    The Natural Language Paradigm (NLP) has proven effective in increasing spontaneous verbalizations for children with autism. This study investigated the use of NLP with older adults with cognitive impairments served at a leisure-based adult day program for seniors. Three individuals with limited spontaneous use of functional language participated…

  10. Metastable spontaneous breaking of N = 2 supersymmetry

    Science.gov (United States)

    Légeret, Benoît; Scrucca, Claudio A.; Smyth, Paul

    2013-05-01

    We show that contrary to the common lore it is possible to spontaneously break N = 2 supersymmetry even in simple theories without constant Fayet-Iliopoulos terms. We consider the most general N = 2 supersymmetric theory with one hypermultiplet and one vector multiplet without Fayet-Iliopoulos terms, and show that metastable supersymmetry breaking vacua can arise if both the hyper-Kähler and the special-Kähler geometries are suitably curved. We then also prove that while all the scalars can be massive, the lightest one is always lighter than the vector boson. Finally, we argue that these results also directly imply that metastable de Sitter vacua can exist in N = 2 supergravity theories with Abelian gaugings and no Fayet-Iliopoulos terms, again contrary to common lore, at least if the cosmological constant is sufficiently large.

  11. Spontaneous Coronary Artery Dissection: The Phantom Menace

    Science.gov (United States)

    Spinthakis, Nikolaos; Abdulkareem, Nada; Farag, Mohamed; Gorog, Diana A.

    2016-01-01

    We present a case of a 66-year-old lady with chest pain, without dynamic 12-lead electrocardiographic (ECG) changes and normal serial troponin. Coronary angiography revealed a linear filing defect in the first obtuse marginal branch of the circumflex artery indicating coronary artery dissection, with superadded thrombus. She was managed medically with dual antiplatelet therapy and has responded well. Spontaneous coronary artery dissection (SCAD) is a rare cause of cardiac chest pain, which can be missed without coronary angiography. Unlike most other lesions in patients with unstable symptoms, where coronary intervention with stenting is recommended, patients with SCAD generally fare better with conservative measures than with intervention, unless there is hemodynamic instability. PMID:28197295

  12. Spontaneous pneumothorax: time to rethink management?

    Science.gov (United States)

    Bintcliffe, Oliver J; Hallifax, Rob J; Edey, Anthony; Feller-Kopman, David; Lee, Y C Gary; Marquette, Charles H; Tschopp, Jean-Marie; West, Douglas; Rahman, Najib M; Maskell, Nick A

    2015-07-01

    There are substantial differences in international guidelines for the management of pneumothorax and much geographical variation in clinical practice. These discrepancies have, in part, been driven by a paucity of high-quality evidence. Advances in diagnostic techniques have increasingly allowed the identification of lung abnormalities in patients previously labelled as having primary spontaneous pneumothorax, a group in whom recommended management differs from those with clinically apparent lung disease. Pathophysiological mechanisms underlying pneumothorax are now better understood and this may have implications for clinical management. Risk stratification of patients at baseline could help to identify subgroups at higher risk of recurrent pneumothorax who would benefit from early intervention to prevent recurrence. Further research into the roles of conservative management, Heimlich valves, digital air-leak monitoring, and pleurodesis at first presentation might lead to an increase in their use in the future.

  13. Information Content of Spontaneous Symmetry Breaking

    CERN Document Server

    Gleiser, Marcelo

    2012-01-01

    We propose a measure of order in the context of nonequilibrium field theory and argue that this measure, which we call relative configurational entropy (RCE), may be used to quantify the emergence of coherent low-entropy configurations, such as time-dependent or time-independent topological and nontopological spatially-extended structures. As an illustration, we investigate the nonequilibrium dynamics of spontaneous symmetry-breaking in three spatial dimensions. In particular, we focus on a model where a real scalar field, prepared initially in a symmetric thermal state, is quenched to a broken-symmetric state. For a certain range of initial temperatures, spatially-localized, long-lived structures known as oscillons emerge in synchrony and remain until the field reaches equilibrium again. We show that the RCE correlates with the number-density of oscillons, thus offering a quantitative measure of the emergence of nonperturbative spatiotemporal patterns that can be generalized to a variety of physical systems.

  14. Collective neutrino oscillations and spontaneous symmetry breaking

    Science.gov (United States)

    Duan, Huaiyu

    2015-08-01

    Neutrino oscillations in a hot and dense astrophysical environment such as a core-collapse supernova pose a challenging, seven-dimensional flavor transport problem. To make the problem even more difficult (and interesting), neutrinos can experience collective oscillations through nonlinear refraction in the dense neutrino medium in this environment. Significant progress has been made in the last decade towards the understanding of collective neutrino oscillations in various simplified neutrino gas models with imposed symmetries and reduced dimensions. However, a series of recent studies seem to have "reset" this progress by showing that these models may not be compatible with collective neutrino oscillations because the latter can break the symmetries spontaneously if they are not imposed. We review some of the key concepts of collective neutrino oscillations by using a few simple toy models. We also elucidate the breaking of spatial and directional symmetries in these models because of collective oscillations.

  15. Collective neutrino oscillations and spontaneous symmetry breaking

    CERN Document Server

    Duan, Huaiyu

    2015-01-01

    Neutrino oscillations in a hot and dense astrophysical environment such as a core-collapse supernova pose a challenging, seven-dimensional flavor transport problem. To make the problem even more difficult (and interesting), neutrinos can experience collective oscillations through nonlinear refraction in the dense neutrino medium in this environment. Significant progress has been made in the last decade towards the understanding of collective neutrino oscillations in various simplified neutrino gas models with imposed symmetries and reduced dimensions. However, a series of recent studies seem to have "reset" this progress by showing that these models may not be compatible with collective neutrino oscillations because the latter can break the symmetries spontaneously if they are not imposed. We review some of the key concepts of collective neutrino oscillations by using a few simple toy models. We also elucidate the breaking of spatial and directional symmetries in these models because of collective oscillation...

  16. Ion cyclotron emission by spontaneous emission

    Energy Technology Data Exchange (ETDEWEB)

    Da Costa, O. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Gresillon, D. [Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises

    1994-07-01

    The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs.

  17. Spontaneous synchrony in power-grid networks

    Science.gov (United States)

    Motter, Adilson E.; Myers, Seth A.; Anghel, Marian; Nishikawa, Takashi

    2013-03-01

    An imperative condition for the functioning of a power-grid network is that its power generators remain synchronized. Disturbances can prompt desynchronization, which is a process that has been involved in large power outages. Here we derive a condition under which the desired synchronous state of a power grid is stable, and use this condition to identify tunable parameters of the generators that are determinants of spontaneous synchronization. Our analysis gives rise to an approach to specify parameter assignments that can enhance synchronization of any given network, which we demonstrate for a selection of both test systems and real power grids. These findings may be used to optimize stability and help devise new control schemes, thus offering an additional layer of protection and contributing to the development of smart grids that can recover from failures in real time.

  18. Spontaneous scalarization: asymmetron as dark matter

    CERN Document Server

    Chen, Pisin; Yokoyama, Jun'ichi

    2015-01-01

    We propose a new scalar-tensor model which induces significant deviation from general relativity inside dense objects like neutron stars, while passing solar-system and terrestrial experiments, extending a model proposed by Damour and Esposito-Farese. Unlike their model, we employ a massive scalar field dubbed asymmetron so that it not only realizes proper cosmic evolution but also can account for the cold dark matter. In our model, asymmetron undergoes spontaneous scalarization inside dense objects, which results in reduction of the gravitational constant by a factor of order unity. This suggests that observational tests of constancy of the gravitational constant in high density phase are the effective ways to look into the asymmetron model.

  19. The spontaneous chlorophyll mutation frequency in barley

    DEFF Research Database (Denmark)

    Jørgensen, Jørgen Helms; Jensen, Hans Peter

    1986-01-01

    A total of 1866 barley plants were progeny tested in the greenhouse. Twenty-five plants segregated for newly arisen, spontaneous chlorophyll mutant genes. Among the total of 470,129 seedlings screened there were 79 mutants (1.7 .+-. 0.6 .times. 10-4). The data are added to data from three similar...... materials and the resulting estimate of the chlorophyll mutant frequency is 1.6 .times. 10-4 in about 1.43 million seedlings. The estimate of the chlorophyll mutation rate per generation is close to 67.3 .times. 10-4 per diploid genome or in the order of 6 .times. 10-7 per locus and haploid genome....

  20. Minimal model for spontaneous quantum synchronization

    Science.gov (United States)

    Benedetti, Claudia; Galve, Fernando; Mandarino, Antonio; Paris, Matteo G. A.; Zambrini, Roberta

    2016-11-01

    We show the emergence of spontaneous synchronization between a pair of detuned quantum oscillators within a harmonic network. Our model does not involve any nonlinearity, driving, or external dissipation, thus providing the simplest scenario for the occurrence of local coherent dynamics in an extended harmonic system. A sufficient condition for synchronization is established by building upon the Rayleigh normal mode approach to vibrational systems. Our results show that mechanisms favoring synchronization, even between oscillators that are not directly coupled to each other, are transient energy depletion and crosstalk. We also address the possible buildup of quantum correlations during synchronization and show that indeed entanglement may be generated in detuned systems, starting from uncorrelated states and without any direct coupling between the two oscillators.

  1. Spontaneous spherical symmetry breaking in atomic confinement

    Science.gov (United States)

    Sveshnikov, Konstantin; Tolokonnikov, Andrey

    2017-07-01

    The effect of spontaneous breaking of initial SO(3) symmetry is shown to be possible for an H-like atom in the ground state, when it is confined in a spherical box under general boundary conditions of "not going out" through the box surface (i.e. third kind or Robin's ones), for a wide range of physically reasonable values of system parameters. The most novel and nontrivial result, which has not been reported previously, is that such an effect takes place not only for attractive, but also for repulsive interactions of atomic electrons with the cavity environment. Moreover, in the limit of a large box size R ≫ aB the regime of an atom, soaring over a plane with boundary condition of "not going out", is reproduced, rather than a spherically symmetric configuration, which would be expected on the basis of the initial SO(3) symmetry of the problem.

  2. Spontaneous electric fields in solid films: spontelectrics

    DEFF Research Database (Denmark)

    Field, David; Plekan, Oksana; Cassidy, Andrew

    2013-01-01

    When dipolar gases are condensed at sufficiently low temperature onto a solid surface, they form films that may spontaneously exhibit electric fields in excess of 108V/m. This effect, called the ‘spontelectric effect’, was recently revealed using an instrument designed to measure scattering...... that the spontelectric field generally decreases monotonically with increased deposition temperature, with the exception of methyl formate that shows an increase beyond a critical range of deposition temperature. Films of spontelectric material show a Curie temperature above which the spontelectric effect disappears....... Heterolayers may also be laid down creating potential wells on the nanoscale. A model is put forward based upon competition between dipole alignment and thermal disorder, which is successful in reproducing the variation of the degree of dipole alignment and the spontelectric field with deposition temperature...

  3. Spontaneous vortex nanodomain arrays at ferroelectric heterointerfaces.

    Science.gov (United States)

    Nelson, Christopher T; Winchester, Benjamin; Zhang, Yi; Kim, Sung-Joo; Melville, Alexander; Adamo, Carolina; Folkman, Chad M; Baek, Seung-Hyub; Eom, Chang-Beom; Schlom, Darrell G; Chen, Long-Qing; Pan, Xiaoqing

    2011-02-09

    The polarization of the ferroelectric BiFeO(3) sub-jected to different electrical boundary conditions by heterointerfaces is imaged with atomic resolution using a spherical aberration-corrected transmission electron microscope. Unusual triangular-shaped nanodomains are seen, and their role in providing polarization closure is understood through phase-field simulations. Heterointerfaces are key to the performance of ferroelectric devices, and this first observation of spontaneous vortex nanodomain arrays at ferroelectric heterointerfaces reveals properties unlike the surrounding film including mixed Ising-Néel domain walls, which will affect switching behavior, and a drastic increase of in-plane polarization. The importance of magnetization closure has long been appreciated in multidomain ferromagnetic systems; imaging this analogous effect with atomic resolution at ferroelectric heterointerfaces provides the ability to see device-relevant interface issues. Extension of this technique to visualize domain dynamics is envisioned.

  4. Recurrent spontaneous multiple pregnancy: a case report

    Directory of Open Access Journals (Sweden)

    Shazia Parveen

    2016-09-01

    Full Text Available Multiple gestations are usually iatrogenic like use of assisted reproductive techniques (ART, infertility treatment but it is rare in spontaneous conception. High order multiple pregnancies (HOMPs are major cause of maternal, fetal and neonatal morbidity. Multiple gestations carries 2 complications either abortion in early gestation or a preterm delivery in late pregnancy (more common. Preterm delivery is common (50% and patient usually delivers by 30-32 weeks. Discordance of fetal growth is very common and even more than in twins. Perinatal loss is inversely related to birth weight. The mothers should be counseled about regular ante natal care (ANC check-ups for early identification of multiple pregnancies so that proper care can be given to prolong the gestational age and reduce the complications associated with multiple pregnancies. [Int J Reprod Contracept Obstet Gynecol 2016; 5(9.000: 3208-3209

  5. Congenital osteofibrous dysplasia Campanacci: spontaneous postbioptic regression.

    Science.gov (United States)

    Jobke, Björn; Bohndorf, Klaus; Vieth, Volker; Werner, Mathias

    2014-04-01

    Osteofibrous dysplasia Campanacci is a rare benign bone tumor most frequently observed in young childhood. The exclusive localization in the tibia is very characteristic. The incidence of congenital primary bone tumors is an absolute rarity. We report a case of a newborn with a histologically proven osteofibrous dysplasia Campanacci at the tibia presenting a regular radiographic follow-up. After a small open biopsy and spontaneous minor fracture, the lesion rapidly remodeled within 1½ months and almost completely regressed with restutio ad integrum. Surgical intervention in this tumor entity at childhood age has been shown to have a high recurrence rate but due to lack of experience with newborns, guidelines do not exist. We analyze the radiologic and histologic differential diagnosis of juvenile adamantinoma and emphasize that congenital peripheral bone tumors should be treated conservatively when malignancy is excluded.

  6. Metastable spontaneous breaking of N=2 supersymmetry

    Energy Technology Data Exchange (ETDEWEB)

    Légeret, Benoît; Scrucca, Claudio A., E-mail: claudio.scrucca@epfl.ch; Smyth, Paul

    2013-05-24

    We show that contrary to the common lore it is possible to spontaneously break N=2 supersymmetry even in simple theories without constant Fayet–Iliopoulos terms. We consider the most general N=2 supersymmetric theory with one hypermultiplet and one vector multiplet without Fayet–Iliopoulos terms, and show that metastable supersymmetry breaking vacua can arise if both the hyper-Kähler and the special-Kähler geometries are suitably curved. We then also prove that while all the scalars can be massive, the lightest one is always lighter than the vector boson. Finally, we argue that these results also directly imply that metastable de Sitter vacua can exist in N=2 supergravity theories with Abelian gaugings and no Fayet–Iliopoulos terms, again contrary to common lore, at least if the cosmological constant is sufficiently large.

  7. Spontaneous closure of midline diastema following frenectomy

    Directory of Open Access Journals (Sweden)

    Koora Kiran

    2007-03-01

    Full Text Available Maxillary midline diastema is a common aesthetic problem in mixed and early permanent dentitions. The space can occur either as a transient malocclusion or created by developmental, pathological or iatrogenical factors. Many innovative therapies varying from restorative procedures such as composite build-up to surgery (frenectomies and orthodontics are available. Although literature says every frenectomy procedure should be preceded by orthodontic treatment, we opted for frenectomy technique without any orthodontic intervention. Presented herewith is a case report of a 9-year-old girl with a high frenal attachment that had caused spacing of the maxillary central incisors. A spontaneous closure of the midline diastema was noted within 2 months following frenectomy. The patient was followed up for 4 months after which the space remained closed and there was no necessity for an orthodontic treatment at a later stage.

  8. Spontaneous closure of midline diastema following frenectomy.

    Science.gov (United States)

    Koora, Kiran; Muthu, M S; Rathna, Prabhu V

    2007-03-01

    Maxillary midline diastema is a common aesthetic problem in mixed and early permanent dentitions. The space can occur either as a transient malocclusion or created by developmental, pathological or iatrogenical factors. Many innovative therapies varying from restorative procedures such as composite build-up to surgery (frenectomies) and orthodontics are available. Although literature says every frenectomy procedure should be preceded by orthodontic treatment, we opted for frenectomy technique without any orthodontic intervention. Presented herewith is a case report of a 9-year-old girl with a high frenal attachment that had caused spacing of the maxillary central incisors. A spontaneous closure of the midline diastema was noted within 2 months following frenectomy. The patient was followed up for 4 months after which the space remained closed and there was no necessity for an orthodontic treatment at a later stage.

  9. A Young Man with Bilateral Spontaneous Pneumothorax

    Directory of Open Access Journals (Sweden)

    Liese Lieve Willemien Verhaert

    2011-01-01

    Full Text Available Case. A 33-year-old male nonsmoker presented with sudden onset of dyspnoea and thoracic pain. Chest radiograph showed a left-sided pneumothorax. Few days later he developed a right-sided pneumothorax. He had a positive family history of pneumothorax. High-resolution computed tomography of the chest showed multiple pulmonary cysts predominantly located in the lower lung regions. We suspected Birt-Hogg-Dubé syndrome (BHD. Conclusion. Birt-Hogg-Dubé syndrome is a rare autosomal dominant inherited genodermatosis and characterised by clinical manifestations including hamartomas of the skin, renal tumors, and pulmonary cysts with spontaneous pneumothorax. BHD is probably underdiagnosed because of the wide variability in its clinical expression. It is important to recognize these patients because of the possibility of developing renal cancer.

  10. Spontaneous mutations and the origin and maintenance of quantitative genetic variation.

    Science.gov (United States)

    Huang, Wen; Lyman, Richard F; Lyman, Rachel A; Carbone, Mary Anna; Harbison, Susan T; Magwire, Michael M; Mackay, Trudy Fc

    2016-05-23

    Mutation and natural selection shape the genetic variation in natural populations. Here, we directly estimated the spontaneous mutation rate by sequencing new Drosophila mutation accumulation lines maintained with minimal natural selection. We inferred strong stabilizing natural selection on quantitative traits because genetic variation among wild-derived inbred lines was much lower than predicted from a neutral model and the mutational effects were much larger than allelic effects of standing polymorphisms. Stabilizing selection could act directly on the traits, or indirectly from pleiotropic effects on fitness. However, our data are not consistent with simple models of mutation-stabilizing selection balance; therefore, further empirical work is needed to assess the balance of evolutionary forces responsible for quantitative genetic variation.

  11. Noncritical generation of nonclassical frequency combs via spontaneous rotational symmetry breaking

    CERN Document Server

    Navarrete-Benlloch, Carlos; de Valcárcel, Germán J

    2016-01-01

    Synchronously pumped optical parametric oscillators (SPOPOs) are optical cavities containing a nonlinear crystal capable of down-converting a frequency comb to lower frequencies. These have received a lot of attention lately, because their intrinsic multimode nature makes them compact sources of quantum correlated light with promising applications in modern quantum information technologies. In this work we show that SPOPOs are also capable of accessing the challenging but interesting regime where spontaneous symmetry breaking plays a crucial role in the quantum properties of the emitted light, difficult to access with any other nonlinear optical cavity. Apart from opening the possibility of studying experimentally this elusive regime of dissipative phase transitions, our predictions will have a practical impact, since we show that spontaneous symmetry breaking provides a specific spatiotemporal mode with perfect squeezing for any value of the system parameters, turning SPOPOs into robust sources of highly non...

  12. Interaction-Driven Spontaneous Quantum Hall Effect on a Kagome Lattice

    Science.gov (United States)

    Zhu, W.; Gong, Shou-Shu; Zeng, Tian-Sheng; Fu, Liang; Sheng, D. N.

    2016-08-01

    Topological states of matter have been widely studied as being driven by an external magnetic field, intrinsic spin-orbital coupling, or magnetic doping. Here, we unveil an interaction-driven spontaneous quantum Hall effect (a Chern insulator) emerging in an extended fermion-Hubbard model on a kagome lattice, based on a state-of-the-art density-matrix renormalization group on cylinder geometry and an exact diagonalization in torus geometry. We first demonstrate that the proposed model exhibits an incompressible liquid phase with doublet degenerate ground states as time-reversal partners. The explicit spontaneous time-reversal symmetry breaking is determined by emergent uniform circulating loop currents between nearest neighbors. Importantly, the fingerprint topological nature of the ground state is characterized by quantized Hall conductance. Thus, we identify the liquid phase as a quantum Hall phase, which provides a "proof-of-principle" demonstration of the interaction-driven topological phase in a topologically trivial noninteracting band.

  13. Is there adequate ionization mechanism of the spontaneous transitions? Quantum-chemical investigation

    Directory of Open Access Journals (Sweden)

    Hovorun D. M.

    2010-09-01

    Full Text Available Aim. To investigate theoretically the adequacy of the ionization mechanism of the spontaneous transitions appearance, using simple molecular models – DNA base pairs, one of which is ionized, and electroneutral and ionized DNA-like conformers of canonical nucleosides. Methods. Non-empirical quantum chemistry, physicochemical kinetics and analysis of the electron density by means of Bader’s atoms in molecules (AIM theory were used. Results. It is established at base pairs that the ionization mechanism of transitions origin doesn’t imply any advantages in comparison with other mechanisms described in literature. However, the protonation/deprotonation of base in any canonical nucleoside significantly perturbs DNA-like conformations of the latter. Conclusions. The ionization mechanism can’t explain entirely the nature of the spontaneous transitions.

  14. Manipulation of spontaneous emission dynamics of organic dyes in the porous silicon matrix.

    Science.gov (United States)

    Makhal, Abhinandan; Kumar, Pushpendra; Lemmens, Peter; Pal, Samir Kumar

    2010-01-01

    The control of the spontaneous emission (SE) rate of dye molecules (4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran (DCM) and Coumarin 523 (C523)) embedded in the Porous Silicon (PS) matrix has been studied using picosecond resolved fluorescence decay and polarization studies. We have shown that the SE rates of the two organic dyes embedded in the PS matrix depend on the relative positions of the emission maxima of the dyes with respect to electronic band gap energy of the PS matrix. We have also explored that the electronic band gap of the host PS matrix can easily be tuned by partial oxidation of the PS and the nature of SE of the embedded dyes can be tuned accordingly. The demonstrated retardation or enhancement of the spontaneous photon emission may enable the application of fluorescent organic molecules in PS matrix in several quantum optical devices including the realization of single photon sources.

  15. Interaction-Driven Spontaneous Quantum Hall Effect on a Kagome Lattice.

    Science.gov (United States)

    Zhu, W; Gong, Shou-Shu; Zeng, Tian-Sheng; Fu, Liang; Sheng, D N

    2016-08-26

    Topological states of matter have been widely studied as being driven by an external magnetic field, intrinsic spin-orbital coupling, or magnetic doping. Here, we unveil an interaction-driven spontaneous quantum Hall effect (a Chern insulator) emerging in an extended fermion-Hubbard model on a kagome lattice, based on a state-of-the-art density-matrix renormalization group on cylinder geometry and an exact diagonalization in torus geometry. We first demonstrate that the proposed model exhibits an incompressible liquid phase with doublet degenerate ground states as time-reversal partners. The explicit spontaneous time-reversal symmetry breaking is determined by emergent uniform circulating loop currents between nearest neighbors. Importantly, the fingerprint topological nature of the ground state is characterized by quantized Hall conductance. Thus, we identify the liquid phase as a quantum Hall phase, which provides a "proof-of-principle" demonstration of the interaction-driven topological phase in a topologically trivial noninteracting band.

  16. Measuring the rates of spontaneous vortex formation in highly oblate Bose-Einstein condensates

    Science.gov (United States)

    Neely, Tyler; Samson, Edward; Bradley, Ashton; Davis, Matthew; Anderson, Brian

    2009-05-01

    By studying the dynamics of the Bose-Einstein condensation transition in highly oblate (˜11:1 aspect ratio) traps, we have measured the dependence of spontaneous vortex formation on BEC growth rate, extending our previous experimental and numerical observations of spontaneous vortex formation in weakly oblate (˜2:1 aspect ratio) traps [1]. Our condensation procedure in these highly oblate traps allows us to create BECs over a large range of growth times, from approximately 200 ms to over 2 s. By characterizing vortex formation vs. BEC growth rate, and comparing experimental and numerical results, the Kibble-Zurek mechanism for topological defect formation may be quantitatively studied in our system. [1] C.N. Weiler, T.W. Neely, D.R. Scherer, A.S. Bradley, M.J. Davis, and B.P. Anderson., Nature 455, 948 (2008).

  17. Posture effects on spontaneous limb movements, alternated stepping, and the leg extension response in neonatal rats.

    Science.gov (United States)

    Mendez-Gallardo, Valerie; Roberto, Megan E; Kauer, Sierra D; Brumley, Michele R

    2016-03-01

    The development of postural control is considered an important factor for the expression of coordinated behavior such as locomotion. In the natural setting of the nest, newborn rat pups adapt their posture to perform behaviors of ecological relevance such as those related to suckling. The current study explores the role of posture in the expression of three behaviors in the newborn rat: spontaneous limb activity, locomotor-like stepping behavior, and the leg extension response (LER). One-day-old rat pups were tested in one of two postures--prone or supine--on each of these behavioral measures. Results showed that pups expressed more spontaneous activity while supine, more stepping while prone, and no differences in LER expression between the two postures. Together these findings show that posture affects the expression of newborn behavior patterns in different ways, and suggest that posture may act as a facilitator or a limiting factor in the expression of different behaviors during early development.

  18. Spontaneous resolution of syringomyelia in an adult patient with tight cisterna magna.

    Science.gov (United States)

    Perrini, Paolo

    2012-12-01

    Spontaneous resolution of syringomyelia in adult patients with Chiari malformation is exceptionally rare, with only 10 cases having been reported. A 21-year-old man working as a carpenter presented with a 1-year history of paresthesias in his right arm. A magnetic resonance imaging scan disclosed a cervicothoracic syrinx associated with tight tonsillar impaction of the cisterna magna without herniation. The patient left the carpentry job and underwent close monitoring with serial clinical and neuroradiological controls. The patient's symptoms gradually disappeared and magnetic resonance imaging studies revealed progressive shrinkage of the syrinx despite persistence of crowding of posterior fossa structures at the level of the foramen magnum. This case suggests that spontaneous resolution of syringomyelia can occasionally be triggered by the cessation of daily physical strain in patients with tight cisterna magna. Health care professionals should be aware that strenuous physical activities could affect the natural history of syringomyelia.

  19. Hyponatremia in Patients with Spontaneous Intracerebral Hemorrhage

    Directory of Open Access Journals (Sweden)

    Jaime Robenolt Gray

    2014-11-01

    Full Text Available Hyponatremia is the most frequently encountered electrolyte abnormality in critically ill patients. Hyponatremia on admission has been identified as an independent predictor of in-hospital mortality in patients with spontaneous intracerebral hemorrhage (sICH. However, the incidence and etiology of hyponatremia (HN during hospitalization in a neurointensive care unit following spontaneous intracerebral hemorrhage (sICH remains unknown. This was a retrospective analysis of consecutive patients admitted to Detroit Receiving Hospital for sICH between January 2006 and July 2009. All serum Na levels were recorded for patients during the ICU stay. HN was defined as Na <135 mmol/L. A total of 99 patients were analyzed with HN developing in 24% of sICH patients. Patients with HN had an average sodium nadir of 130 ± 3 mmol/L and an average time from admission to sodium <135 mmol/L of 3.9 ± 5.7 days. The most common cause of hyponatremia was syndrome of inappropriate antidiuretic hormone (90% of HN patients. Patients with HN were more likely to have fever (50% vs. 23%; p = 0.01, infection (58% vs. 28%; p = 0.007 as well as a longer hospital length of stay (14 (8–25 vs. 6 (3–9 days; p < 0.001. Of the patients who developed HN, fifteen (62.5% patients developed HN in the first week following sICH. This shows HN has a fairly high incidence following sICH. The presence of HN is associated with longer hospital length of stays and higher rates of patient complications, which may result in worse patient outcomes. Further study is necessary to characterize the clinical relevance and treatment of HN in this population.

  20. PLURALIZING NATURE

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    Denmark is widely recognised for its democratic approach to planning and the idea of planning for the common good. This interest in the common good and common values seems also to be reflected in the way which nature restoration is planned and managed – one common nature directed by the public...... authorities. But nature restoration is far from being a neural undertaking. Just like any other type of heritage production it can be the source of dissonance – ‘our’ nature is not necessary ‘their’ nature. Often this dissonance is managed in ways, which are not particular sensitive to site......-specificity. As exemplified by the Skjern River Restoration Project (1999-2003), one interpretation of the landscape sometimes suppresses other valid interpretations neglecting its diverse history. However, evidence from Switzerland suggests that planning for the common good, in the case of nature restoration, does...

  1. Nature seconded

    OpenAIRE

    Gough, Tim

    2002-01-01

    Heidegger�s remark that the banks of the river (representing nature in its supposedly pure state) only become apparent because of the presence of the bridge (representing the artificial in its supposed opposition to that nature) will lead this presentation to a discussion of whether or not the idea of �nature� as prior to architecture remains unequivocally valid. If nature/the site - that which claims to come before the artificial/architecture - only appears as a result of the presence ...

  2. Spontaneous water filtration of bio-inspired membrane

    Science.gov (United States)

    Kim, Kiwoong; Kim, Hyejeong; Lee, Sang Joon

    2016-11-01

    Water is one of the most important elements for plants, because it is essential for various metabolic activities. Thus, water management systems of vascular plants, such as water collection and water filtration have been optimized through a long history. In this view point, bio-inspired technologies can be developed by mimicking the nature's strategies for the survival of the fittest. However, most of the underlying biophysical features of the optimized water management systems remain unsolved In this study, the biophysical characteristics of water filtration phenomena in the roots of mangrove are experimentally investigated. To understand water-filtration features of the mangrove, the morphological structures of its roots are analyzed. The electrokinetic properties of the root surface are also examined. Based on the quantitatively analyzed information, filtration of sodium ions in the roots are visualized. Motivated by this mechanism, spontaneous desalination mechanism in the root of mangrove is proposed by combining the electrokinetics and hydrodynamic transportation of ions. This study would be helpful for understanding the water-filtration mechanism of the roots of mangrove and developing a new bio-inspired desalination technology. This research was financially supported by the National Research Foundation (NRF) of Korea (Contract Grant Number: 2008-0061991).

  3. Spontaneous lesions in aged captive raccoons (Procyon lotor).

    Science.gov (United States)

    Hamir, Amir N

    2011-05-01

    In nature, free-ranging raccoons typically do not live longer than 2 y; most raccoons in the wild die young due to accidents and diseases. Therefore, few data are available regarding lesions associated with advancing age in raccoons. This communication documents the lesions present in raccoons (7 male; 3 female) that were older than 7 y and had been used as breeders at a commercial facility in central Iowa. The most frequent microscopic lesions in these raccoons included accumulation of iron pigment in livers and spleens (10 of 10 animals evaluated), neuroaxonal degeneration in caudal medulla (10 of 10), vascular mineralization (psammoma body) in choroid plexus (9 of 10), myocardial inclusions (7 of 8), and cystic endometrial hyperplasia (2 of 3). Other conditions were seen with less prevalence. Except for the detection of gastritis with bacteria in the gastric mucosa of 1 raccoon, the presence of inflammatory cells in 3 choroid plexuses, and the presence of Lafora bodies in the brain of 1 animal, all conditions observed had previously been reported in raccoons. Surprisingly, islet-cell amyloidosis, previously observed as common incidental finding in older captive raccoons, was not seen in any of the raccoons we examined. Because free-ranging raccoons are distributed over wide geographic areas, their local environment may have considerable influence on the range of spontaneous lesions that would occur in raccoons obtained from a specific location. Therefore, the lesions found in these raccoons from central Iowa may differ from those of other raccoon populations.

  4. Optical instabilities and spontaneous light emission in moving media

    Science.gov (United States)

    Silveirinha, Mario

    2015-03-01

    We show that when an uncharged plasmonic material is set in relative motion with respect to another uncharged polarizable body the system may be electromagnetically unstable. Particularly, when the relative velocity of the two bodies is enforced to remain constant the system may support natural oscillations that grow exponentially with time, even in presence of realistic material loss and dispersion. It is proven that a friction-type force acts on the moving bodies to oppose their relative motion. Hence, the optical instabilities result from the conversion of kinetic energy into electromagnetic energy. This new purely classical phenomenon is analogous to the Cherenkov and Smith-Purcell effects but for uncharged polarizable matter. We link the optical instabilities to a spontaneous parity-time symmetry breaking of the system, and demonstrate the possibility of optical amplification of a light pulse in the broken parity-time symmetry regime. This work is supported in part by Fundação para a Ciência e a Tecnologia Grant Number PTDC/EEI-TEL/2764/2012.

  5. Spontaneous structural transition in phospholipid-inspired aromatic phosphopeptide nanostructures.

    Science.gov (United States)

    Pellach, Michal; Atsmon-Raz, Yoav; Simonovsky, Eyal; Gottlieb, Hugo; Jacoby, Guy; Beck, Roy; Adler-Abramovich, Lihi; Miller, Yifat; Gazit, Ehud

    2015-01-01

    Phospholipid membranes could be considered a prime example of the ability of nature to produce complex yet ordered structures, by spontaneous and efficient self-assembly. Inspired by the unique properties and architecture of phospholipids, we designed simple amphiphilic decapeptides, intended to fold in the center of the peptide sequence, with a phosphorylated serine "head" located within a central turn segment, and two hydrophobic "tails". The molecular design also included the integration of the diphenylalanine motif, previously shown to facilitate self-assembly and increase nanostructure stability. Secondary structure analysis of the peptides indeed indicated the presence of stabilized conformations in solution, with a central turn connecting two hydrophobic "tails", and interactions between the hydrophobic strands. The mechanisms of assembly into supramolecular structures involved structural transitions between different morphologies, which occurred over several hours, leading to the formation of distinctive nanostructures, including half-elliptical nanosheets and curved tapes. The phosphopeptide building blocks appear to self-assemble via a particular combination of aromatic, hydrophobic and ionic interactions, as well as hydrogen bonding, as demonstrated by proposed constructed simulated models of the peptides and self-assembled nanostructures. Molecular dynamics simulations also gave insight into mechanisms of structural transitions of the nanostructures at a molecular level. Because of the biocompatibility of peptides, the phosphopeptide assemblies allow for expansion of the library of biomolecular nanostructures available for future design and application of biomedical devices.

  6. Spontaneous spiking in an autaptic Hodgkin-Huxley setup

    Science.gov (United States)

    Li, Yunyun; Schmid, Gerhard; Hänggi, Peter; Schimansky-Geier, Lutz

    2010-12-01

    The effect of intrinsic channel noise is investigated for the dynamic response of a neuronal cell with a delayed feedback loop. The loop is based on the so-called autapse phenomenon in which dendrites establish connections not only to neighboring cells but also to its own axon. The biophysical modeling is achieved in terms of a stochastic Hodgkin-Huxley model containing such a built in delayed feedback. The fluctuations stem from intrinsic channel noise, being caused by the stochastic nature of the gating dynamics of ion channels. The influence of the delayed stimulus is systematically analyzed with respect to the coupling parameter and the delay time in terms of the interspike interval histograms and the average interspike interval. The delayed feedback manifests itself in the occurrence of bursting and a rich multimodal interspike interval distribution, exhibiting a delay-induced reduction in the spontaneous spiking activity at characteristic frequencies. Moreover, a specific frequency-locking mechanism is detected for the mean interspike interval.

  7. Spontaneous rickets in the wild arctic fox Alopex lagopus

    Energy Technology Data Exchange (ETDEWEB)

    Ogden, J.A.; Conlogue, G.J.

    1981-10-01

    Normal and rachitic, skeletally immature arctic foxes (Alopex lagopus) were subjected to physical examination, roentgenographic studies, and in some cases histologic studies. The involved animals had active rickets coupled with antecedent normal diaphyseal bone formation. Evaluation of all the long bones showed highly variable manifestations of the disease, which undoubtedly reflect different rates of physeal endochondral transformation and metaphyseal remodeling. Histologic examination showed distinct patterns of widening of the physes and variable osteodystrophy in the trabecular and cortical bone of the metaphyses and epiphyseal ossification centers. These aforementioned factors certainly would necessitate different regional calcium needs and, therefore, different regional responses to an overall calcium deficiency. The physes involved in the most rapid growth rates in this period showed the most widening of the growth plate, and the most dystrophic changes in the metaphysis. Skeletal injuries, including metaphyseal fractures and slow-down of longitudinal growth (particularly in the ulna) were also evident. Because of apparent dietary differences in the affected and normal fox kits, this juvenile-onset disease was presumed due to calcium-deficient intake following weaning. To the best of our knowledge this is the first report of spontaneously occurring rickets in a wild animal in its natural habitat. There are several possible mechanisms for the variable widening of the physis and the loss of bone mineralization in these fox kits: calcium-deficient diet, binding of calcium in the bowel by high phosphorus intake, secondary hyperparathyroidism, and vitamin A toxicity.

  8. Spontaneous Heterotopic Pregnancy: Dual Case Report and Review of Literature

    Directory of Open Access Journals (Sweden)

    Annika Chadee

    2016-01-01

    Full Text Available Introduction. Heterotopic pregnancy is a rare complication usually seen in populations at risk for ectopic pregnancy or those undergoing fertility treatments. It is a potentially dangerous condition occurring in only 1 in 30,000 spontaneous pregnancies. With the advent of Assisted Reproduction Techniques (ART and ovulation induction, the overall incidence of heterotopic pregnancy has risen to approximately 1 in 3,900 pregnancies. Other risk factors include a history of pelvic inflammatory disease (PID, tubal damage, pelvic surgery, uterine Mullerian abnormalities, and prior tubal surgery. Heterotopic pregnancy is a potentially fatal condition, rarely occurring in natural conception cycles. Most commonly, heterotopic pregnancy is diagnosed at the time of rupture when surgical management is required. Case. This paper represents two cases of heterotopic pregnancies as well as a literature review. Conclusion. Heterotopic pregnancy should be suspected in patients with an adnexal mass, even in the absence of risk factors. Clinicians must be alert to the fact that confirming an intrauterine pregnancy clinically or by ultrasound does not exclude the coexistence of an ectopic pregnancy. A high index of suspicion in women is needed for early and timely diagnosis, and management with laparotomy or laparoscopy can result in a favorable and successful obstetrical outcome.

  9. Incidence of heart failure in infarcted rats that die spontaneously

    Directory of Open Access Journals (Sweden)

    R.L.G. Flumignan

    2006-10-01

    Full Text Available The present study reports for the first time the incidence of congestive heart failure (CHF in previously infarcted rats that died spontaneously. Previously, pulmonary (PWC and hepatic (HWC water contents were determined in normal rats: 14 control animals were evaluated immediately after sacrifice, 8 placed in a refrigerator for 24 h, and 10 left at room temperature for 24 h. In the infarcted group, 9 rats died before (acute and 28 died 48 h after (chronic myocardial infarction. Thirteen chronic animals were submitted only to autopsy (N = 13, whereas PWC and HWC were also determined in the others (N = 15. Seven rats survived 48 h and died during anesthesia. Notably, PWC differed in normal rats: ambient (75.7 ± 1.3% < control (77.5 ± 0.7% < refrigerator (79.1 ± 1.4% and there were no differences with respect to HWC. No clinical signs of CHF (dyspnea, lethargy or foot edema were observed in infarcted rats before death. PWC was elevated in all chronic and anesthetized rats. HWC was increased in 48% of chronic and in all anesthetized rats. Our data showed that PWC needs to be evaluated before 24 h post mortem and that CHF is the rule in chronic infarcted rats suffering natural death. The congestive syndrome cannot be diagnosed correctly in rats by clinical signs alone, as previously proposed.

  10. Spontaneous emission control in a tunable hybrid photonic system

    NARCIS (Netherlands)

    Frimmer, M.; Koenderink, A.F.

    2013-01-01

    We experimentally demonstrate control of the rate of spontaneous emission in a tunable hybrid photonic system that consists of two canonical building blocks for spontaneous emission control, an optical antenna and a mirror, each providing a modification of the local density of optical states (LDOS).

  11. Spontaneous emission and nonlinear effects in photonic bandgap materials

    Science.gov (United States)

    Fogel, Ishella S.; Bendickson, Jon M.; Tocci, Michael D.; Bloemer, Mark J.; Scalora, Michael; Bowden, Charles M.; Dowling, Jonathan P.

    1998-03-01

    We summarize and review our theoretical and experimental work on spontaneous emission and nonlinear effects in one-dimensional, photonic bandgap (PBG) structures. We present a new result: a method for calculating the normal-mode solutions - and hence the spontaneous emission of embedded emitters - in an arbitrary, linear, lossless, one-dimensional, PBG structure.

  12. Spontaneous Play and Imagination in Everyday Science Classroom Practice

    Science.gov (United States)

    Andrée, Maria; Lager-Nyqvist, Lotta

    2013-01-01

    In science education, students sometimes create and engage in spontaneous science-oriented play where ideas about science and scientists are put to use. However, in previous research, little attention has been given to the role of informal spontaneous play in school science classrooms. We argue that, in order to enhance our understanding of…

  13. Video-Assisted Thoracic Surgery in Spontaneous Pneumothorax

    Directory of Open Access Journals (Sweden)

    Calvin SH Ng

    2002-01-01

    Full Text Available The proven safety and efficacy of minimal access video-assisted thoracic surgery has changed the way that spontaneous pneumothorax is managed. This review presents some of the experiences of the decade, discusses the controversies and reviews the current video-assisted thoracic surgical management of spontaneous pneumothorax.

  14. Spontaneous resolution of optic nerve coloboma-associated retinal detachment.

    Science.gov (United States)

    Ying, Michelle S; Fuller, Jeff; Young, Joshua; Marcus, Dennis M

    2004-01-01

    We report a congenital neurosensory retinal detachment associated with an optic nerve coloboma with subsequent spontaneous reattachment. This represents the earliest reported case of such a clinical situation. An observation period is recommended for infants with this clinical course to allow for the opportunity of spontaneous reattachment.

  15. Spontaneous Breaking of Spatial and Spin Symmetry in Spinor Condensates

    DEFF Research Database (Denmark)

    Scherer, M.; Lücke, B.; Gebreyesus, G.;

    2010-01-01

    Parametric amplification of quantum fluctuations constitutes a fundamental mechanism for spontaneous symmetry breaking. In our experiments, a spinor condensate acts as a parametric amplifier of spin modes, resulting in a twofold spontaneous breaking of spatial and spin symmetry in the amplified...

  16. Prevention of spontaneous fires by directed nitrogen supply

    Energy Technology Data Exchange (ETDEWEB)

    Chumak, A.S.; Pashkovsky, P.S.; Yaremchuk, M.A. [RESPIRATOR Research-and-Manufacturing, Donetsk (Ukraine). Association on Mine Rescue Work

    2001-07-01

    The most widespread means of localization and fighting spontaneous fires are inert gases, water-air and inert foams. However, the use of these techniques is developed insufficiently in the mines of Ukraine. In the first place it concerns the directed inertization of the goaf. Analysis of cases shows that following mining-and-geological and mining factors influence the endogenic fire hazard most strongly. Air losses into the goaf exert the decisive influence on development of the process of spontaneous ignition of coal. The zone of caved rocks is constantly ventilated at their expense. It creates places of spontaneous combustion of coal. The performed investigations of air losses through the goaf of the panels allowed to construct graphs of the dependence of air losses along the whole length of the zone of active ventilation of the goaf for the most typical ventilation schemes. Determination of bounds of the zone of fire-hazardous air losses, points of appearance of spontaneous heating places permits purposeful nitrogen supply only there where places of spontaneous heating are formed. The point of the matter of the method of spontaneous fires prevention consists in lowering the oxygen volume fraction up to 14% in the places of spontaneous heating being predicted, which excepts spontaneous ignition. 8 refs., 6 figs.

  17. Computed Tomography Features of Spontaneously Perforated Pyometra: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Chan, K.S.; Tan, C.K.; Mak, C.W.; Chia, C.C.; Kuo, C.Y.; Yu, W.L. [Chi-Mei Medical Center, Tainan, Taiwan (China). Depts. of Intensive Care Medicine, Radiology, Obstetrics and Gynecology, and Surgery

    2006-03-15

    Spontaneous perforation of pyometra is an extremely rare emergent gynecologic disease. We report a 73-year-old woman with a spontaneously perforated pyometra presenting with acute abdomen in the emergency department. A dedicated computed tomography examination of the abdominal and pelvic regions revealed the diagnosis. The patient recovered well after surgical intervention and antibiotic treatment.

  18. Spontaneous and cytokine induced basophil adhesion evaluated by microtiter assay

    DEFF Research Database (Denmark)

    Quan, Sha; Poulsen, Lars K; Reimert, Claus Michael

    2002-01-01

    by the histamine content of the adhering basophils. The spontaneous adhesion to fibronectin was higher than to laminin and collagen type I. Both spontaneous adhesion to fibronectin and interleukin-3 (IL-3), interleukin-5 (IL-5), granulocyte/macrophage colony stimulating factor (GM-CSF) induced adhesion to BSA...

  19. 49 CFR 172.547 - SPONTANEOUSLY COMBUSTIBLE placard.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false SPONTANEOUSLY COMBUSTIBLE placard. 172.547 Section 172.547 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS... REQUIREMENTS, AND SECURITY PLANS Placarding § 172.547 SPONTANEOUSLY COMBUSTIBLE placard. (a) Except for size...

  20. STUDY ON MAJOR FACTORS INFLUENCING SPONTANEOUS COMBUSTION OF COAL

    Institute of Scientific and Technical Information of China (English)

    Deng Jun; Xu Jingcai; Zhang Xinghai

    2000-01-01

    This paper theoretically analyzes major factors influencing spontaneous combustion of coal, such as molecule structure of coal, porosity, temperature, concentration of oxygen, coal thickness, velocity of face advance, and so on; and probes into how they affect the process of spontaneous combustion of coal, which is of momentous significance to predict or control self-ignition of coal.